Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1350859 > unrolled thread
| Started by | Mauro Carvalho Chehab <mchehab@osg.samsung.com> |
|---|---|
| First post | 2016-03-05 11:10 +0100 |
| Last post | 2016-03-07 23:20 +0100 |
| Articles | 5 — 2 participants |
Back to article view | Back to linux.kernel
This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by
below is the oldest one visible, not the original post.
Re: [PATCH v5 22/22] sound/usb: Use Media Controller API to share media resources Mauro Carvalho Chehab <mchehab@osg.samsung.com> - 2016-03-05 11:10 +0100
Re: [PATCH v5 22/22] sound/usb: Use Media Controller API to share media resources Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-07 15:20 +0100
Re: [PATCH v5 22/22] sound/usb: Use Media Controller API to share media resources Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-07 21:10 +0100
Re: [PATCH v5 22/22] sound/usb: Use Media Controller API to share media resources Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-07 23:10 +0100
Re: [PATCH v5 22/22] sound/usb: Use Media Controller API to share media resources Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-07 23:20 +0100
| From | Mauro Carvalho Chehab <mchehab@osg.samsung.com> |
|---|---|
| Date | 2016-03-05 11:10 +0100 |
| Subject | Re: [PATCH v5 22/22] sound/usb: Use Media Controller API to share media resources |
| Message-ID | <r9hjQ-4yQ-17@gated-at.bofh.it> |
Em Wed, 2 Mar 2016 09:50:31 -0700
Shuah Khan <shuahkh@osg.samsung.com> escreveu:
> Change ALSA driver to use Media Controller API to
> share media resources with DVB and V4L2 drivers
> on a AU0828 media device. Media Controller specific
> initialization is done after sound card is registered.
> ALSA creates Media interface and entity function graph
> nodes for Control, Mixer, PCM Playback, and PCM Capture
> devices.
>
> snd_usb_hw_params() will call Media Controller enable
> source handler interface to request the media resource.
> If resource request is granted, it will release it from
> snd_usb_hw_free(). If resource is busy, -EBUSY is returned.
>
> Media specific cleanup is done in usb_audio_disconnect().
>
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> Acked-by: Takashi Iwai <tiwai@suse.de>
Shuah, by looking at the produced graphs:
https://mchehab.fedorapeople.org/mc-next-gen/au0828_test/
I'm noticing the lack of ALSA I/O entities in the diagram
(MEDIA_ENT_F_AUDIO_CAPTURE). The mixer there is not connected.
Could you please check what's happening?
Those are the relevant dmesg data:
[ 19.017276] usbcore: registered new interface driver snd-usb-audio
[ 230.706102] Linux video capture interface: v2.00
[ 230.856983] au0828: au0828 driver loaded
[ 231.230612] au0828: i2c bus registered
[ 231.822006] tveeprom 5-0050: Hauppauge model 72001, rev E1H3, serial# 4035199481
[ 231.822991] tveeprom 5-0050: MAC address is 00:0d:fe:84:41:f9
[ 231.823955] tveeprom 5-0050: tuner model is Xceive XC5000C (idx 173, type 88)
[ 231.824782] tveeprom 5-0050: TV standards NTSC(M) ATSC/DVB Digital (eeprom 0x88)
[ 231.825272] tveeprom 5-0050: audio processor is AU8522 (idx 44)
[ 231.825276] tveeprom 5-0050: decoder processor is AU8522 (idx 42)
[ 231.825280] tveeprom 5-0050: has no radio, has IR receiver, has no IR transmitter
[ 231.825283] au0828: hauppauge_eeprom: hauppauge eeprom: model=72001
[ 231.857567] au8522 5-0047: creating new instance
[ 231.857879] au8522_decoder creating new instance...
[ 231.910525] tuner 5-0061: Setting mode_mask to 0x06
[ 231.910532] tuner 5-0061: tuner 0x61: Tuner type absent
[ 231.910535] tuner 5-0061: Tuner -1 found with type(s) Radio TV.
[ 231.911343] tuner 5-0061: Calling set_type_addr for type=88, addr=0x61, mode=0x04, config=ffffffffa0e64100
[ 231.911347] tuner 5-0061: defining GPIO callback
[ 231.934896] xc5000 5-0061: creating new instance
[ 231.954664] xc5000: Successfully identified at address 0x61
[ 231.954987] xc5000: Firmware has not been loaded previously
[ 231.955327] tuner 5-0061: type set to Xceive XC5000
[ 231.955330] tuner 5-0061: au0828 tuner I2C addr 0xc2 with type 88 used for 0x04
[ 233.622614] au8522 5-0047: attaching existing instance
[ 233.636061] xc5000 5-0061: attaching existing instance
[ 233.645775] xc5000: Successfully identified at address 0x61
[ 233.646034] xc5000: Firmware has not been loaded previously
[ 233.646461] DVB: registering new adapter (au0828)
[ 233.647575] usb 2-3.3: DVB: registering adapter 0 frontend 0 (Auvitek AU8522 QAM/8VSB Frontend)...
[ 233.648344] dvb_create_media_entity: media entity 'Auvitek AU8522 QAM/8VSB Frontend' registered.
[ 233.656105] dvb_create_media_entity: media entity 'dvb-demux' registered.
[ 234.166644] IR keymap rc-hauppauge not found
[ 234.166962] Registered IR keymap rc-empty
[ 234.178055] input: au0828 IR (Hauppauge HVR950Q) as /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3.3/rc/rc0/input14
[ 234.203311] rc rc0: au0828 IR (Hauppauge HVR950Q) as /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3.3/rc/rc0
[ 234.207828] au0828: Remote controller au0828 IR (Hauppauge HVR950Q) initalized
[ 234.208270] au0828: Registered device AU0828 [Hauppauge HVR950Q]
[ 234.212073] usbcore: registered new interface driver au0828
[ 234.230371] lirc_dev: IR Remote Control driver registered, major 243
[ 234.257555] rc rc0: lirc_dev: driver ir-lirc-codec (au0828-input) registered at minor = 0
[ 234.257960] IR LIRC bridge handler initialized
(as au0828 is blacklisted, snd-usb-audio was probed first)
====xxxx====
I'm also getting some other weird behavior when removing/reinserting
the modules a few times. OK, officially we don't support it, but,
as devices can be bind/unbind all the times, removing modules is
a way to simulate such things. Also, I use it a lot while testing
USB drivers ;)
This one is after removing both the media drivers and snd-usb-audio,
and then modprobing snd-usb-audio:
[ 1839.510587] BUG: sleeping function called from invalid context at mm/slub.c:1289
[ 1839.510881] in_atomic(): 1, irqs_disabled(): 0, pid: 3479, name: modprobe
[ 1839.511157] 4 locks held by modprobe/3479:
[ 1839.511415] #0: (&dev->mutex){......}, at: [<ffffffff81ce8933>] __driver_attach+0xa3/0x160
[ 1839.512381] #1: (&dev->mutex){......}, at: [<ffffffff81ce8941>] __driver_attach+0xb1/0x160
[ 1839.512388] #2: (register_mutex#5){+.+.+.}, at: [<ffffffffa10596c7>] usb_audio_probe+0x257/0x1c90 [snd_usb_audio]
[ 1839.512401] #3: (&(&mdev->lock)->rlock){+.+.+.}, at: [<ffffffffa0e6051b>] media_device_register_entity+0x1cb/0x700 [media]
[ 1839.512412] CPU: 2 PID: 3479 Comm: modprobe Not tainted 4.5.0-rc3+ #49
[ 1839.512415] Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015
[ 1839.512417] 0000000000000000 ffff8803b3f6f288 ffffffff81933901 ffff8803c4bae000
[ 1839.512422] ffff8803c4bae5c8 ffff8803b3f6f2b0 ffffffff811c6af5 ffff8803c4bae000
[ 1839.512427] ffffffff8285d7f6 0000000000000509 ffff8803b3f6f2f0 ffffffff811c6ce5
[ 1839.512432] Call Trace:
[ 1839.512436] [<ffffffff81933901>] dump_stack+0x85/0xc4
[ 1839.512440] [<ffffffff811c6af5>] ___might_sleep+0x245/0x3a0
[ 1839.512443] [<ffffffff811c6ce5>] __might_sleep+0x95/0x1a0
[ 1839.512446] [<ffffffff8155aade>] kmem_cache_alloc_trace+0x20e/0x300
[ 1839.512451] [<ffffffffa0e66e3d>] ? media_add_link+0x4d/0x140 [media]
[ 1839.512455] [<ffffffffa0e66e3d>] media_add_link+0x4d/0x140 [media]
[ 1839.512459] [<ffffffffa0e69931>] media_create_pad_link+0xa1/0x600 [media]
[ 1839.512463] [<ffffffffa0fe11b3>] au0828_media_graph_notify+0x173/0x360 [au0828]
[ 1839.512467] [<ffffffffa0e68a6a>] ? media_gobj_create+0x1ba/0x480 [media]
[ 1839.512471] [<ffffffffa0e606fb>] media_device_register_entity+0x3ab/0x700 [media]
[ 1839.512475] [<ffffffffa0e60350>] ? media_device_release_devres+0x10/0x10 [media]
[ 1839.512479] [<ffffffff8124068d>] ? trace_hardirqs_on+0xd/0x10
[ 1839.512482] [<ffffffff8159f992>] ? create_object+0x5a2/0x940
[ 1839.512485] [<ffffffff8159f3f0>] ? kmemleak_disable+0x90/0x90
[ 1839.512489] [<ffffffff8159f3f0>] ? kmemleak_disable+0x90/0x90
[ 1839.512497] [<ffffffffa109722c>] ? media_snd_mixer_init+0x16c/0x500 [snd_usb_audio]
[ 1839.512501] [<ffffffff8155f696>] ? kasan_unpoison_shadow+0x36/0x50
[ 1839.512504] [<ffffffff8155f70e>] ? kasan_kmalloc+0x5e/0x70
[ 1839.512511] [<ffffffffa1097352>] media_snd_mixer_init+0x292/0x500 [snd_usb_audio]
[ 1839.512519] [<ffffffffa1097693>] media_snd_device_create+0xd3/0x2e0 [snd_usb_audio]
[ 1839.512525] [<ffffffffa1059b05>] usb_audio_probe+0x695/0x1c90 [snd_usb_audio]
[ 1839.512529] [<ffffffff8128b217>] ? debug_lockdep_rcu_enabled+0x77/0x90
[ 1839.512536] [<ffffffffa1059470>] ? snd_usb_create_stream+0x4e0/0x4e0 [snd_usb_audio]
[ 1839.512540] [<ffffffff812404fa>] ? trace_hardirqs_on_caller+0x40a/0x590
[ 1839.512543] [<ffffffff8124068d>] ? trace_hardirqs_on+0xd/0x10
[ 1839.512546] [<ffffffff81dbb1dd>] usb_probe_interface+0x45d/0x940
[ 1839.512550] [<ffffffff81ce7e7a>] driver_probe_device+0x21a/0xc30
[ 1839.512553] [<ffffffff81ce8890>] ? driver_probe_device+0xc30/0xc30
[ 1839.512556] [<ffffffff81ce89b1>] __driver_attach+0x121/0x160
[ 1839.512559] [<ffffffff81ce21bf>] bus_for_each_dev+0x11f/0x1a0
[ 1839.512562] [<ffffffff81ce20a0>] ? subsys_dev_iter_exit+0x10/0x10
[ 1839.512565] [<ffffffff822e7be7>] ? _raw_spin_unlock+0x27/0x40
[ 1839.512568] [<ffffffff81ce6cdd>] driver_attach+0x3d/0x50
[ 1839.512571] [<ffffffff81ce5df9>] bus_add_driver+0x4c9/0x770
[ 1839.512575] [<ffffffff81cea39c>] driver_register+0x18c/0x3b0
[ 1839.512578] [<ffffffff81250f92>] ? __raw_spin_lock_init+0x32/0x100
[ 1839.512581] [<ffffffff81db6e98>] usb_register_driver+0x1f8/0x440
[ 1839.512584] [<ffffffff810021a1>] ? do_one_initcall+0x131/0x300
[ 1839.512587] [<ffffffffa10d8000>] ? 0xffffffffa10d8000
[ 1839.512594] [<ffffffffa10d801e>] usb_audio_driver_init+0x1e/0x1000 [snd_usb_audio]
[ 1839.512597] [<ffffffff810021b1>] do_one_initcall+0x141/0x300
[ 1839.512600] [<ffffffff81002070>] ? try_to_run_init_process+0x40/0x40
[ 1839.512603] [<ffffffff8155f696>] ? kasan_unpoison_shadow+0x36/0x50
[ 1839.512606] [<ffffffff8155f696>] ? kasan_unpoison_shadow+0x36/0x50
[ 1839.512609] [<ffffffff8155f7a7>] ? __asan_register_globals+0x87/0xa0
[ 1839.512613] [<ffffffff8144d8eb>] do_init_module+0x1d0/0x5ad
[ 1839.512617] [<ffffffff812f27b6>] load_module+0x6666/0x9ba0
[ 1839.512620] [<ffffffff812e9e20>] ? symbol_put_addr+0x50/0x50
[ 1839.512627] [<ffffffff812ec150>] ? module_frob_arch_sections+0x20/0x20
[ 1839.512630] [<ffffffff815be010>] ? open_exec+0x50/0x50
[ 1839.512634] [<ffffffff8116716b>] ? ns_capable+0x5b/0xd0
[ 1839.512637] [<ffffffff812f5fe8>] SyS_finit_module+0x108/0x130
[ 1839.512640] [<ffffffff812f5ee0>] ? SyS_init_module+0x1f0/0x1f0
[ 1839.512643] [<ffffffff81004044>] ? lockdep_sys_exit_thunk+0x12/0x14
[ 1839.512647] [<ffffffff822e8636>] entry_SYSCALL_64_fastpath+0x16/0x76
[ 1839.514027] usbcore: registered new interface driver snd-usb-audio
And an extra kmemleak issue:
unreferenced object 0xffff8803bcbacf30 (size 128):
comm "modprobe", pid 2625, jiffies 4294950803 (age 1715.788s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff822cf76e>] kmemleak_alloc+0x4e/0xb0
[<ffffffff8155ab06>] kmem_cache_alloc_trace+0x236/0x300
[<ffffffff81937eb2>] ida_pre_get+0x1a2/0x250
[<ffffffff81938005>] ida_simple_get+0xa5/0x170
[<ffffffffa0f1469a>] 0xffffffffa0f1469a
[<ffffffffa0fe6951>] au0828_dvb_register+0xe21/0x12c0 [au0828]
[<ffffffffa0fd1d92>] vb2_thread+0xbb2/0xc10 [videobuf2_core]
[<ffffffff81dbb1dd>] usb_probe_interface+0x45d/0x940
[<ffffffff81ce7e7a>] driver_probe_device+0x21a/0xc30
[<ffffffff81ce89b1>] __driver_attach+0x121/0x160
[<ffffffff81ce21bf>] bus_for_each_dev+0x11f/0x1a0
[<ffffffff81ce6cdd>] driver_attach+0x3d/0x50
[<ffffffff81ce5df9>] bus_add_driver+0x4c9/0x770
[<ffffffff81cea39c>] driver_register+0x18c/0x3b0
[<ffffffff81db6e98>] usb_register_driver+0x1f8/0x440
[<ffffffffa0fb80b7>] au8522_get_frontend+0xb7/0x160 [au8522_dig]
I did one extra module removal/reinsert, and this time, I got lots
of bugs. Full dmesg is at:
http://pastebin.com/LEX5LD5K
The Kernel hanged after a while with (at the serial console - with
kind of explain why the message is truncated):
[ 2117.282666] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#2] SMP KASAN
[ 2117.284074] Modules linked in: videobuf2_v4l2 videobuf2_core tveeprom dvb_core rc_core v4l2_common videodev snd_usb_audio media cpufreq_powersave cpufreq_conservative cpufreq_userspace cpufreq_stats parport_pc ppdev lp parport snd_hda_codec_hdmi intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel iTCO_wdt iTCO_vendor_support kvm irqbypass crct10dif_pclmul crc32_
[toc] | [next] | [standalone]
| From | Shuah Khan <shuahkh@osg.samsung.com> |
|---|---|
| Date | 2016-03-07 15:20 +0100 |
| Message-ID | <ra4aS-3TP-11@gated-at.bofh.it> |
| In reply to | #1350859 |
On 03/05/2016 03:00 AM, Mauro Carvalho Chehab wrote:
> Em Wed, 2 Mar 2016 09:50:31 -0700
> Shuah Khan <shuahkh@osg.samsung.com> escreveu:
>
>> Change ALSA driver to use Media Controller API to
>> share media resources with DVB and V4L2 drivers
>> on a AU0828 media device. Media Controller specific
>> initialization is done after sound card is registered.
>> ALSA creates Media interface and entity function graph
>> nodes for Control, Mixer, PCM Playback, and PCM Capture
>> devices.
>>
>> snd_usb_hw_params() will call Media Controller enable
>> source handler interface to request the media resource.
>> If resource request is granted, it will release it from
>> snd_usb_hw_free(). If resource is busy, -EBUSY is returned.
>>
>> Media specific cleanup is done in usb_audio_disconnect().
>>
>> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
>> Acked-by: Takashi Iwai <tiwai@suse.de>
>
> Shuah, by looking at the produced graphs:
> https://mchehab.fedorapeople.org/mc-next-gen/au0828_test/
>
> I'm noticing the lack of ALSA I/O entities in the diagram
> (MEDIA_ENT_F_AUDIO_CAPTURE). The mixer there is not connected.
>
> Could you please check what's happening?
Mauro,
Did you pull in this patch that fixes the graph problem:
https://www.mail-archive.com/linux-media@vger.kernel.org/msg95047.html
If you haven't, could you please pull this in.
>
> Those are the relevant dmesg data:
>
> [ 19.017276] usbcore: registered new interface driver snd-usb-audio
> [ 230.706102] Linux video capture interface: v2.00
> [ 230.856983] au0828: au0828 driver loaded
> [ 231.230612] au0828: i2c bus registered
> [ 231.822006] tveeprom 5-0050: Hauppauge model 72001, rev E1H3, serial# 4035199481
> [ 231.822991] tveeprom 5-0050: MAC address is 00:0d:fe:84:41:f9
> [ 231.823955] tveeprom 5-0050: tuner model is Xceive XC5000C (idx 173, type 88)
> [ 231.824782] tveeprom 5-0050: TV standards NTSC(M) ATSC/DVB Digital (eeprom 0x88)
> [ 231.825272] tveeprom 5-0050: audio processor is AU8522 (idx 44)
> [ 231.825276] tveeprom 5-0050: decoder processor is AU8522 (idx 42)
> [ 231.825280] tveeprom 5-0050: has no radio, has IR receiver, has no IR transmitter
> [ 231.825283] au0828: hauppauge_eeprom: hauppauge eeprom: model=72001
> [ 231.857567] au8522 5-0047: creating new instance
> [ 231.857879] au8522_decoder creating new instance...
> [ 231.910525] tuner 5-0061: Setting mode_mask to 0x06
> [ 231.910532] tuner 5-0061: tuner 0x61: Tuner type absent
> [ 231.910535] tuner 5-0061: Tuner -1 found with type(s) Radio TV.
> [ 231.911343] tuner 5-0061: Calling set_type_addr for type=88, addr=0x61, mode=0x04, config=ffffffffa0e64100
> [ 231.911347] tuner 5-0061: defining GPIO callback
> [ 231.934896] xc5000 5-0061: creating new instance
> [ 231.954664] xc5000: Successfully identified at address 0x61
> [ 231.954987] xc5000: Firmware has not been loaded previously
> [ 231.955327] tuner 5-0061: type set to Xceive XC5000
> [ 231.955330] tuner 5-0061: au0828 tuner I2C addr 0xc2 with type 88 used for 0x04
> [ 233.622614] au8522 5-0047: attaching existing instance
> [ 233.636061] xc5000 5-0061: attaching existing instance
> [ 233.645775] xc5000: Successfully identified at address 0x61
> [ 233.646034] xc5000: Firmware has not been loaded previously
> [ 233.646461] DVB: registering new adapter (au0828)
> [ 233.647575] usb 2-3.3: DVB: registering adapter 0 frontend 0 (Auvitek AU8522 QAM/8VSB Frontend)...
> [ 233.648344] dvb_create_media_entity: media entity 'Auvitek AU8522 QAM/8VSB Frontend' registered.
> [ 233.656105] dvb_create_media_entity: media entity 'dvb-demux' registered.
> [ 234.166644] IR keymap rc-hauppauge not found
> [ 234.166962] Registered IR keymap rc-empty
> [ 234.178055] input: au0828 IR (Hauppauge HVR950Q) as /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3.3/rc/rc0/input14
> [ 234.203311] rc rc0: au0828 IR (Hauppauge HVR950Q) as /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3.3/rc/rc0
> [ 234.207828] au0828: Remote controller au0828 IR (Hauppauge HVR950Q) initalized
> [ 234.208270] au0828: Registered device AU0828 [Hauppauge HVR950Q]
> [ 234.212073] usbcore: registered new interface driver au0828
> [ 234.230371] lirc_dev: IR Remote Control driver registered, major 243
> [ 234.257555] rc rc0: lirc_dev: driver ir-lirc-codec (au0828-input) registered at minor = 0
> [ 234.257960] IR LIRC bridge handler initialized
>
> (as au0828 is blacklisted, snd-usb-audio was probed first)
>
> ====xxxx====
>
> I'm also getting some other weird behavior when removing/reinserting
> the modules a few times. OK, officially we don't support it, but,
> as devices can be bind/unbind all the times, removing modules is
> a way to simulate such things. Also, I use it a lot while testing
> USB drivers ;)
I will do more testing on this. I didn't see any problems when
I fixed the graph patch above - I will do more on the latest
media branch today.
thanks,
-- Shuah
>
> This one is after removing both the media drivers and snd-usb-audio,
> and then modprobing snd-usb-audio:
>
> [ 1839.510587] BUG: sleeping function called from invalid context at mm/slub.c:1289
> [ 1839.510881] in_atomic(): 1, irqs_disabled(): 0, pid: 3479, name: modprobe
> [ 1839.511157] 4 locks held by modprobe/3479:
> [ 1839.511415] #0: (&dev->mutex){......}, at: [<ffffffff81ce8933>] __driver_attach+0xa3/0x160
> [ 1839.512381] #1: (&dev->mutex){......}, at: [<ffffffff81ce8941>] __driver_attach+0xb1/0x160
> [ 1839.512388] #2: (register_mutex#5){+.+.+.}, at: [<ffffffffa10596c7>] usb_audio_probe+0x257/0x1c90 [snd_usb_audio]
> [ 1839.512401] #3: (&(&mdev->lock)->rlock){+.+.+.}, at: [<ffffffffa0e6051b>] media_device_register_entity+0x1cb/0x700 [media]
> [ 1839.512412] CPU: 2 PID: 3479 Comm: modprobe Not tainted 4.5.0-rc3+ #49
> [ 1839.512415] Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015
> [ 1839.512417] 0000000000000000 ffff8803b3f6f288 ffffffff81933901 ffff8803c4bae000
> [ 1839.512422] ffff8803c4bae5c8 ffff8803b3f6f2b0 ffffffff811c6af5 ffff8803c4bae000
> [ 1839.512427] ffffffff8285d7f6 0000000000000509 ffff8803b3f6f2f0 ffffffff811c6ce5
> [ 1839.512432] Call Trace:
> [ 1839.512436] [<ffffffff81933901>] dump_stack+0x85/0xc4
> [ 1839.512440] [<ffffffff811c6af5>] ___might_sleep+0x245/0x3a0
> [ 1839.512443] [<ffffffff811c6ce5>] __might_sleep+0x95/0x1a0
> [ 1839.512446] [<ffffffff8155aade>] kmem_cache_alloc_trace+0x20e/0x300
> [ 1839.512451] [<ffffffffa0e66e3d>] ? media_add_link+0x4d/0x140 [media]
> [ 1839.512455] [<ffffffffa0e66e3d>] media_add_link+0x4d/0x140 [media]
> [ 1839.512459] [<ffffffffa0e69931>] media_create_pad_link+0xa1/0x600 [media]
> [ 1839.512463] [<ffffffffa0fe11b3>] au0828_media_graph_notify+0x173/0x360 [au0828]
> [ 1839.512467] [<ffffffffa0e68a6a>] ? media_gobj_create+0x1ba/0x480 [media]
> [ 1839.512471] [<ffffffffa0e606fb>] media_device_register_entity+0x3ab/0x700 [media]
> [ 1839.512475] [<ffffffffa0e60350>] ? media_device_release_devres+0x10/0x10 [media]
> [ 1839.512479] [<ffffffff8124068d>] ? trace_hardirqs_on+0xd/0x10
> [ 1839.512482] [<ffffffff8159f992>] ? create_object+0x5a2/0x940
> [ 1839.512485] [<ffffffff8159f3f0>] ? kmemleak_disable+0x90/0x90
> [ 1839.512489] [<ffffffff8159f3f0>] ? kmemleak_disable+0x90/0x90
> [ 1839.512497] [<ffffffffa109722c>] ? media_snd_mixer_init+0x16c/0x500 [snd_usb_audio]
> [ 1839.512501] [<ffffffff8155f696>] ? kasan_unpoison_shadow+0x36/0x50
> [ 1839.512504] [<ffffffff8155f70e>] ? kasan_kmalloc+0x5e/0x70
> [ 1839.512511] [<ffffffffa1097352>] media_snd_mixer_init+0x292/0x500 [snd_usb_audio]
> [ 1839.512519] [<ffffffffa1097693>] media_snd_device_create+0xd3/0x2e0 [snd_usb_audio]
> [ 1839.512525] [<ffffffffa1059b05>] usb_audio_probe+0x695/0x1c90 [snd_usb_audio]
> [ 1839.512529] [<ffffffff8128b217>] ? debug_lockdep_rcu_enabled+0x77/0x90
> [ 1839.512536] [<ffffffffa1059470>] ? snd_usb_create_stream+0x4e0/0x4e0 [snd_usb_audio]
> [ 1839.512540] [<ffffffff812404fa>] ? trace_hardirqs_on_caller+0x40a/0x590
> [ 1839.512543] [<ffffffff8124068d>] ? trace_hardirqs_on+0xd/0x10
> [ 1839.512546] [<ffffffff81dbb1dd>] usb_probe_interface+0x45d/0x940
> [ 1839.512550] [<ffffffff81ce7e7a>] driver_probe_device+0x21a/0xc30
> [ 1839.512553] [<ffffffff81ce8890>] ? driver_probe_device+0xc30/0xc30
> [ 1839.512556] [<ffffffff81ce89b1>] __driver_attach+0x121/0x160
> [ 1839.512559] [<ffffffff81ce21bf>] bus_for_each_dev+0x11f/0x1a0
> [ 1839.512562] [<ffffffff81ce20a0>] ? subsys_dev_iter_exit+0x10/0x10
> [ 1839.512565] [<ffffffff822e7be7>] ? _raw_spin_unlock+0x27/0x40
> [ 1839.512568] [<ffffffff81ce6cdd>] driver_attach+0x3d/0x50
> [ 1839.512571] [<ffffffff81ce5df9>] bus_add_driver+0x4c9/0x770
> [ 1839.512575] [<ffffffff81cea39c>] driver_register+0x18c/0x3b0
> [ 1839.512578] [<ffffffff81250f92>] ? __raw_spin_lock_init+0x32/0x100
> [ 1839.512581] [<ffffffff81db6e98>] usb_register_driver+0x1f8/0x440
> [ 1839.512584] [<ffffffff810021a1>] ? do_one_initcall+0x131/0x300
> [ 1839.512587] [<ffffffffa10d8000>] ? 0xffffffffa10d8000
> [ 1839.512594] [<ffffffffa10d801e>] usb_audio_driver_init+0x1e/0x1000 [snd_usb_audio]
> [ 1839.512597] [<ffffffff810021b1>] do_one_initcall+0x141/0x300
> [ 1839.512600] [<ffffffff81002070>] ? try_to_run_init_process+0x40/0x40
> [ 1839.512603] [<ffffffff8155f696>] ? kasan_unpoison_shadow+0x36/0x50
> [ 1839.512606] [<ffffffff8155f696>] ? kasan_unpoison_shadow+0x36/0x50
> [ 1839.512609] [<ffffffff8155f7a7>] ? __asan_register_globals+0x87/0xa0
> [ 1839.512613] [<ffffffff8144d8eb>] do_init_module+0x1d0/0x5ad
> [ 1839.512617] [<ffffffff812f27b6>] load_module+0x6666/0x9ba0
> [ 1839.512620] [<ffffffff812e9e20>] ? symbol_put_addr+0x50/0x50
> [ 1839.512627] [<ffffffff812ec150>] ? module_frob_arch_sections+0x20/0x20
> [ 1839.512630] [<ffffffff815be010>] ? open_exec+0x50/0x50
> [ 1839.512634] [<ffffffff8116716b>] ? ns_capable+0x5b/0xd0
> [ 1839.512637] [<ffffffff812f5fe8>] SyS_finit_module+0x108/0x130
> [ 1839.512640] [<ffffffff812f5ee0>] ? SyS_init_module+0x1f0/0x1f0
> [ 1839.512643] [<ffffffff81004044>] ? lockdep_sys_exit_thunk+0x12/0x14
> [ 1839.512647] [<ffffffff822e8636>] entry_SYSCALL_64_fastpath+0x16/0x76
> [ 1839.514027] usbcore: registered new interface driver snd-usb-audio
>
> And an extra kmemleak issue:
>
> unreferenced object 0xffff8803bcbacf30 (size 128):
> comm "modprobe", pid 2625, jiffies 4294950803 (age 1715.788s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff822cf76e>] kmemleak_alloc+0x4e/0xb0
> [<ffffffff8155ab06>] kmem_cache_alloc_trace+0x236/0x300
> [<ffffffff81937eb2>] ida_pre_get+0x1a2/0x250
> [<ffffffff81938005>] ida_simple_get+0xa5/0x170
> [<ffffffffa0f1469a>] 0xffffffffa0f1469a
> [<ffffffffa0fe6951>] au0828_dvb_register+0xe21/0x12c0 [au0828]
> [<ffffffffa0fd1d92>] vb2_thread+0xbb2/0xc10 [videobuf2_core]
> [<ffffffff81dbb1dd>] usb_probe_interface+0x45d/0x940
> [<ffffffff81ce7e7a>] driver_probe_device+0x21a/0xc30
> [<ffffffff81ce89b1>] __driver_attach+0x121/0x160
> [<ffffffff81ce21bf>] bus_for_each_dev+0x11f/0x1a0
> [<ffffffff81ce6cdd>] driver_attach+0x3d/0x50
> [<ffffffff81ce5df9>] bus_add_driver+0x4c9/0x770
> [<ffffffff81cea39c>] driver_register+0x18c/0x3b0
> [<ffffffff81db6e98>] usb_register_driver+0x1f8/0x440
> [<ffffffffa0fb80b7>] au8522_get_frontend+0xb7/0x160 [au8522_dig]
>
> I did one extra module removal/reinsert, and this time, I got lots
> of bugs. Full dmesg is at:
> http://pastebin.com/LEX5LD5K
>
> The Kernel hanged after a while with (at the serial console - with
> kind of explain why the message is truncated):
>
> [ 2117.282666] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#2] SMP KASAN
> [ 2117.284074] Modules linked in: videobuf2_v4l2 videobuf2_core tveeprom dvb_core rc_core v4l2_common videodev snd_usb_audio media cpufreq_powersave cpufreq_conservative cpufreq_userspace cpufreq_stats parport_pc ppdev lp parport snd_hda_codec_hdmi intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel iTCO_wdt iTCO_vendor_support kvm irqbypass crct10dif_pclmul crc32_
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978
[toc] | [prev] | [next] | [standalone]
| From | Shuah Khan <shuahkh@osg.samsung.com> |
|---|---|
| Date | 2016-03-07 21:10 +0100 |
| Message-ID | <ra9DA-7xE-7@gated-at.bofh.it> |
| In reply to | #1351619 |
On 03/07/2016 07:16 AM, Shuah Khan wrote: > On 03/05/2016 03:00 AM, Mauro Carvalho Chehab wrote: >> Em Wed, 2 Mar 2016 09:50:31 -0700 >> Shuah Khan <shuahkh@osg.samsung.com> escreveu: >> >>> Change ALSA driver to use Media Controller API to >>> share media resources with DVB and V4L2 drivers >>> on a AU0828 media device. Media Controller specific >>> initialization is done after sound card is registered. >>> ALSA creates Media interface and entity function graph >>> nodes for Control, Mixer, PCM Playback, and PCM Capture >>> devices. >>> >>> snd_usb_hw_params() will call Media Controller enable >>> source handler interface to request the media resource. >>> If resource request is granted, it will release it from >>> snd_usb_hw_free(). If resource is busy, -EBUSY is returned. >>> >>> Media specific cleanup is done in usb_audio_disconnect(). >>> >>> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> >>> Acked-by: Takashi Iwai <tiwai@suse.de> >> >> Shuah, by looking at the produced graphs: >> https://mchehab.fedorapeople.org/mc-next-gen/au0828_test/ >> >> I'm noticing the lack of ALSA I/O entities in the diagram >> (MEDIA_ENT_F_AUDIO_CAPTURE). The mixer there is not connected. >> >> Could you please check what's happening? > > Mauro, > > Did you pull in this patch that fixes the graph problem: > > https://www.mail-archive.com/linux-media@vger.kernel.org/msg95047.html > > If you haven't, could you please pull this in. > You do have the above patch in the latest linux_media git. I couldn't reproduce the problem you are seeing. Here is what I did. - Blacklisted au0828 and forcing snd_usb_audio probe first. Then I generated a graph that shows just the audio nodes. - And then did a modprobe and generated full graph. https://drive.google.com/folderview?id=0B0NIL0BQg-AlejFpR19Cb1RGYVk&usp=drive_web I see that in you graph, mixer gets connected to decoder, but the rest of the audio nodes are missing from the graph. MEDIA_ENT_F_AUDIO_CAPTURE gets created from snd_usb_pcm_open() and gets deleted from free_substream(). Is it possible, for some reason, either snd_usb_pcm_open() fails or free_substream() is called? thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh@osg.samsung.com | (970) 217-8978
[toc] | [prev] | [next] | [standalone]
| From | Shuah Khan <shuahkh@osg.samsung.com> |
|---|---|
| Date | 2016-03-07 23:10 +0100 |
| Message-ID | <rabvI-ik-31@gated-at.bofh.it> |
| In reply to | #1350859 |
On 03/05/2016 03:00 AM, Mauro Carvalho Chehab wrote: > Em Wed, 2 Mar 2016 09:50:31 -0700 > Shuah Khan <shuahkh@osg.samsung.com> escreveu: > >> Change ALSA driver to use Media Controller API to >> share media resources with DVB and V4L2 drivers >> on a AU0828 media device. Media Controller specific >> initialization is done after sound card is registered. >> ALSA creates Media interface and entity function graph >> nodes for Control, Mixer, PCM Playback, and PCM Capture >> devices. >> >> snd_usb_hw_params() will call Media Controller enable >> source handler interface to request the media resource. >> If resource request is granted, it will release it from >> snd_usb_hw_free(). If resource is busy, -EBUSY is returned. >> >> Media specific cleanup is done in usb_audio_disconnect(). >> >> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> >> Acked-by: Takashi Iwai <tiwai@suse.de> > > Shuah, by looking at the produced graphs: > https://mchehab.fedorapeople.org/mc-next-gen/au0828_test/ > > I'm noticing the lack of ALSA I/O entities in the diagram > (MEDIA_ENT_F_AUDIO_CAPTURE). The mixer there is not connected. > > Could you please check what's happening? > > Those are the relevant dmesg data: > > [ 19.017276] usbcore: registered new interface driver snd-usb-audio > [ 230.706102] Linux video capture interface: v2.00 > [ 230.856983] au0828: au0828 driver loaded > [ 231.230612] au0828: i2c bus registered > [ 231.822006] tveeprom 5-0050: Hauppauge model 72001, rev E1H3, serial# 4035199481 > [ 231.822991] tveeprom 5-0050: MAC address is 00:0d:fe:84:41:f9 > [ 231.823955] tveeprom 5-0050: tuner model is Xceive XC5000C (idx 173, type 88) > [ 231.824782] tveeprom 5-0050: TV standards NTSC(M) ATSC/DVB Digital (eeprom 0x88) > [ 231.825272] tveeprom 5-0050: audio processor is AU8522 (idx 44) > [ 231.825276] tveeprom 5-0050: decoder processor is AU8522 (idx 42) > [ 231.825280] tveeprom 5-0050: has no radio, has IR receiver, has no IR transmitter > [ 231.825283] au0828: hauppauge_eeprom: hauppauge eeprom: model=72001 > [ 231.857567] au8522 5-0047: creating new instance > [ 231.857879] au8522_decoder creating new instance... > [ 231.910525] tuner 5-0061: Setting mode_mask to 0x06 > [ 231.910532] tuner 5-0061: tuner 0x61: Tuner type absent > [ 231.910535] tuner 5-0061: Tuner -1 found with type(s) Radio TV. > [ 231.911343] tuner 5-0061: Calling set_type_addr for type=88, addr=0x61, mode=0x04, config=ffffffffa0e64100 > [ 231.911347] tuner 5-0061: defining GPIO callback > [ 231.934896] xc5000 5-0061: creating new instance > [ 231.954664] xc5000: Successfully identified at address 0x61 > [ 231.954987] xc5000: Firmware has not been loaded previously > [ 231.955327] tuner 5-0061: type set to Xceive XC5000 > [ 231.955330] tuner 5-0061: au0828 tuner I2C addr 0xc2 with type 88 used for 0x04 > [ 233.622614] au8522 5-0047: attaching existing instance > [ 233.636061] xc5000 5-0061: attaching existing instance > [ 233.645775] xc5000: Successfully identified at address 0x61 > [ 233.646034] xc5000: Firmware has not been loaded previously > [ 233.646461] DVB: registering new adapter (au0828) > [ 233.647575] usb 2-3.3: DVB: registering adapter 0 frontend 0 (Auvitek AU8522 QAM/8VSB Frontend)... > [ 233.648344] dvb_create_media_entity: media entity 'Auvitek AU8522 QAM/8VSB Frontend' registered. > [ 233.656105] dvb_create_media_entity: media entity 'dvb-demux' registered. > [ 234.166644] IR keymap rc-hauppauge not found > [ 234.166962] Registered IR keymap rc-empty > [ 234.178055] input: au0828 IR (Hauppauge HVR950Q) as /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3.3/rc/rc0/input14 > [ 234.203311] rc rc0: au0828 IR (Hauppauge HVR950Q) as /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3.3/rc/rc0 > [ 234.207828] au0828: Remote controller au0828 IR (Hauppauge HVR950Q) initalized > [ 234.208270] au0828: Registered device AU0828 [Hauppauge HVR950Q] > [ 234.212073] usbcore: registered new interface driver au0828 > [ 234.230371] lirc_dev: IR Remote Control driver registered, major 243 > [ 234.257555] rc rc0: lirc_dev: driver ir-lirc-codec (au0828-input) registered at minor = 0 > [ 234.257960] IR LIRC bridge handler initialized > > (as au0828 is blacklisted, snd-usb-audio was probed first) > > ====xxxx==== > > I'm also getting some other weird behavior when removing/reinserting > the modules a few times. OK, officially we don't support it, but, > as devices can be bind/unbind all the times, removing modules is > a way to simulate such things. Also, I use it a lot while testing > USB drivers ;) > > This one is after removing both the media drivers and snd-usb-audio, > and then modprobing snd-usb-audio: > I did see some issues when I did the following sequence: - blacklisted au0828 and snd-usb-audio was probed first graph is good just with audio entities as expected - modprobed au0828 - graph looks good. - rmmod au0828 - no problems seen in dmesg - modprobe au0828 - problems kasan reports bad access etc. http://pastebin.com/FFqNzx9G Here is what's going on after each step: blacklisted au0828 and snd-usb-audio was probed first 1. snd-usb-audio creates media device and registers it Creates its graph etc. 2. modprobed au0828 au0828 finds the media device created and registered. Adds its graph 3. rmmod au0828 Even though there are no problems reported, at this time media device is unregistered, and /dev/mediaX is removed. We still have snd_usb-audio and media device. As media device is a device resource on usb device parent, it will still be there, but no way to access the device itself, because it is no longer registered. 4. modprobe au0828 At this point, au0828 finds the media device as it still there, registers it and adds its graph. No audio graph present at this time. Please note that the media device will not be deleted until the last put on the parent usb struct device. So even when both snd-usb-audio, and au0828 modules are removed, media device is still there without its graph and associated devnode (/dev/mediax is removed). This isn't bad, however, media_device could still have stale information. e.g: enable/disable handlers - when au0828 is removed, these are no longer valid. Could be cleaned up in media device unregister just like entity_notify() handler gets deleted from media device unregister. At the moment, either driver can call unregister and same cleanup happens. I will send a patch to do enable/disable hanlder cleanup in unregister path. However, the root of the problem is media device is still there without its graph and associated devnode (/dev/mediax is removed) when any one of the drivers is removed. This leaves the remaining drivers in a degenerate state. The problem can be solved with some handshaking at unregister time. We could add a callback for each if the drivers to handle media device unregister. However, that would add delays in device removal path when all the drivers exit. I think it will be hard to handle all the corner cases without adding run-time overhead. Any thoughts on whether we want to unofficially support being able to remove individual drivers? thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh@osg.samsung.com | (970) 217-8978
[toc] | [prev] | [next] | [standalone]
| From | Shuah Khan <shuahkh@osg.samsung.com> |
|---|---|
| Date | 2016-03-07 23:20 +0100 |
| Message-ID | <rabFn-m1-3@gated-at.bofh.it> |
| In reply to | #1350859 |
On 03/05/2016 03:00 AM, Mauro Carvalho Chehab wrote: > Em Wed, 2 Mar 2016 09:50:31 -0700 > Shuah Khan <shuahkh@osg.samsung.com> escreveu: > >> Change ALSA driver to use Media Controller API to >> share media resources with DVB and V4L2 drivers >> on a AU0828 media device. Media Controller specific >> initialization is done after sound card is registered. >> ALSA creates Media interface and entity function graph >> nodes for Control, Mixer, PCM Playback, and PCM Capture >> devices. >> >> snd_usb_hw_params() will call Media Controller enable >> source handler interface to request the media resource. >> If resource request is granted, it will release it from >> snd_usb_hw_free(). If resource is busy, -EBUSY is returned. >> >> Media specific cleanup is done in usb_audio_disconnect(). >> >> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> >> Acked-by: Takashi Iwai <tiwai@suse.de> > > Shuah, by looking at the produced graphs: > https://mchehab.fedorapeople.org/mc-next-gen/au0828_test/ > > I'm noticing the lack of ALSA I/O entities in the diagram > (MEDIA_ENT_F_AUDIO_CAPTURE). The mixer there is not connected. > > Could you please check what's happening? > > Those are the relevant dmesg data: > > [ 19.017276] usbcore: registered new interface driver snd-usb-audio > [ 230.706102] Linux video capture interface: v2.00 > [ 230.856983] au0828: au0828 driver loaded > [ 231.230612] au0828: i2c bus registered > [ 231.822006] tveeprom 5-0050: Hauppauge model 72001, rev E1H3, serial# 4035199481 > [ 231.822991] tveeprom 5-0050: MAC address is 00:0d:fe:84:41:f9 > [ 231.823955] tveeprom 5-0050: tuner model is Xceive XC5000C (idx 173, type 88) > [ 231.824782] tveeprom 5-0050: TV standards NTSC(M) ATSC/DVB Digital (eeprom 0x88) > [ 231.825272] tveeprom 5-0050: audio processor is AU8522 (idx 44) > [ 231.825276] tveeprom 5-0050: decoder processor is AU8522 (idx 42) > [ 231.825280] tveeprom 5-0050: has no radio, has IR receiver, has no IR transmitter > [ 231.825283] au0828: hauppauge_eeprom: hauppauge eeprom: model=72001 > [ 231.857567] au8522 5-0047: creating new instance > [ 231.857879] au8522_decoder creating new instance... > [ 231.910525] tuner 5-0061: Setting mode_mask to 0x06 > [ 231.910532] tuner 5-0061: tuner 0x61: Tuner type absent > [ 231.910535] tuner 5-0061: Tuner -1 found with type(s) Radio TV. > [ 231.911343] tuner 5-0061: Calling set_type_addr for type=88, addr=0x61, mode=0x04, config=ffffffffa0e64100 > [ 231.911347] tuner 5-0061: defining GPIO callback > [ 231.934896] xc5000 5-0061: creating new instance > [ 231.954664] xc5000: Successfully identified at address 0x61 > [ 231.954987] xc5000: Firmware has not been loaded previously > [ 231.955327] tuner 5-0061: type set to Xceive XC5000 > [ 231.955330] tuner 5-0061: au0828 tuner I2C addr 0xc2 with type 88 used for 0x04 > [ 233.622614] au8522 5-0047: attaching existing instance > [ 233.636061] xc5000 5-0061: attaching existing instance > [ 233.645775] xc5000: Successfully identified at address 0x61 > [ 233.646034] xc5000: Firmware has not been loaded previously > [ 233.646461] DVB: registering new adapter (au0828) > [ 233.647575] usb 2-3.3: DVB: registering adapter 0 frontend 0 (Auvitek AU8522 QAM/8VSB Frontend)... > [ 233.648344] dvb_create_media_entity: media entity 'Auvitek AU8522 QAM/8VSB Frontend' registered. > [ 233.656105] dvb_create_media_entity: media entity 'dvb-demux' registered. > [ 234.166644] IR keymap rc-hauppauge not found > [ 234.166962] Registered IR keymap rc-empty > [ 234.178055] input: au0828 IR (Hauppauge HVR950Q) as /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3.3/rc/rc0/input14 > [ 234.203311] rc rc0: au0828 IR (Hauppauge HVR950Q) as /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3.3/rc/rc0 > [ 234.207828] au0828: Remote controller au0828 IR (Hauppauge HVR950Q) initalized > [ 234.208270] au0828: Registered device AU0828 [Hauppauge HVR950Q] > [ 234.212073] usbcore: registered new interface driver au0828 > [ 234.230371] lirc_dev: IR Remote Control driver registered, major 243 > [ 234.257555] rc rc0: lirc_dev: driver ir-lirc-codec (au0828-input) registered at minor = 0 > [ 234.257960] IR LIRC bridge handler initialized > > (as au0828 is blacklisted, snd-usb-audio was probed first) > > ====xxxx==== > > I'm also getting some other weird behavior when removing/reinserting > the modules a few times. OK, officially we don't support it, but, > as devices can be bind/unbind all the times, removing modules is > a way to simulate such things. Also, I use it a lot while testing > USB drivers ;) > > This one is after removing both the media drivers and snd-usb-audio, > and then modprobing snd-usb-audio: > I did see some issues when I did the following sequence: - blacklisted au0828 and snd-usb-audio was probed first graph is good just with audio entities as expected - modprobed au0828 - graph looks good. - rmmod au0828 - no problems seen in dmesg - modprobe au0828 - problems kasan reports bad access etc. http://pastebin.com/FFqNzx9G Here is what's going on after each step: blacklisted au0828 and snd-usb-audio was probed first 1. snd-usb-audio creates media device and registers it Creates its graph etc. 2. modprobed au0828 au0828 finds the media device created and registered. Adds its graph 3. rmmod au0828 Even though there are no problems reported, at this time media device is unregistered, and /dev/mediaX is removed. We still have snd_usb-audio and media device. As media device is a device resource on usb device parent, it will still be there, but no way to access the device itself, because it is no longer registered. 4. modprobe au0828 At this point, au0828 finds the media device as it still there, registers it and adds its graph. No audio graph present at this time. Please note that the media device will not be deleted until the last put on the parent usb struct device. So even when both snd-usb-audio, and au0828 modules are removed, media device is still there without its graph and associated devnode (/dev/mediax is removed). This isn't bad, however, media_device could still have stale information. e.g: enable/disable handlers - when au0828 is removed, these are no longer valid. Could be cleaned up in media device unregister just like entity_notify() handler gets deleted from media device unregister. At the moment, either driver can call unregister and same cleanup happens. I will send a patch to do enable/disable handler cleanup in unregister path. However, the root of the problem is media device is still there without its graph and associated devnode (/dev/mediax is removed) when any one of the drivers is removed. This leaves the remaining drivers in a degenerate state. The problem can be solved with some handshaking at unregister time. We could add a callback for each if the drivers to handle media device unregister. However, that would add delays in device removal path when all the drivers exit. I think it will be hard to handle all the corner cases without adding run-time overhead. Any thoughts on whether we want to unofficially support being able to remove individual drivers? thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh@osg.samsung.com | (970) 217-8978
[toc] | [prev] | [standalone]
Back to top | Article view | linux.kernel
csiph-web