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Groups > linux.kernel > #1593056
| From | Jiri Slaby <jslaby@suse.cz> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.12 081/113] USB: serial: ftdi_sio: fix extreme low-latency setting |
| Date | 2017-03-06 10:30 +0100 |
| Message-ID | <thX7S-68q-51@gated-at.bofh.it> (permalink) |
| References | <thWY9-64J-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Johan Hovold <johan@kernel.org>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit c6dce2626606ef16434802989466636bc28c1419 upstream.
Since commit 557aaa7ffab6 ("ft232: support the ASYNC_LOW_LATENCY
flag") the FTDI driver has been using a receive latency-timer value of
1 ms instead of the device default of 16 ms.
The latency timer is used to periodically empty a non-full receive
buffer, but a status header is always sent when the timer expires
including when the buffer is empty. This means that a two-byte bulk
message is received every millisecond also for an otherwise idle port as
long as it is open.
Let's restore the pre-2009 behaviour which reduces the rate of the
status messages to 1/16th (e.g. interrupt frequency drops from 1 kHz to
62.5 Hz) by not setting ASYNC_LOW_LATENCY by default.
Anyone willing to pay the price for the minimum-latency behaviour should
set the flag explicitly instead using the TIOCSSERIAL ioctl or a tool
such as setserial (e.g. setserial /dev/ttyUSB0 low_latency).
Note that since commit 0cbd81a9f6ba ("USB: ftdi_sio: remove
tty->low_latency") the ASYNC_LOW_LATENCY flag has no other effects but
to set a minimal latency timer.
Reported-by: Antoine Aubert <a.aubert@overkiz.com>
Fixes: 557aaa7ffab6 ("ft232: support the ASYNC_LOW_LATENCY flag")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/usb/serial/ftdi_sio.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 5ed104787474..e2e564a071fc 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1829,8 +1829,6 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port)
mutex_init(&priv->cfg_lock);
- priv->flags = ASYNC_LOW_LATENCY;
-
if (quirk && quirk->port_probe)
quirk->port_probe(priv);
--
2.12.0
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[PATCH 3.12 000/113] 3.12.71-stable review Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:20 +0100
[PATCH 3.12 001/113] x86/Kconfig: Simplify X86_IO_APIC dependencies Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:20 +0100
[PATCH 3.12 092/113] ocfs2: do not write error flag to user structure we cannot copy from/to Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:20 +0100
[PATCH 3.12 111/113] USB: cdc-acm: fix double usb_autopm_put_interface() in acm_port_activate() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:20 +0100
[PATCH 3.12 089/113] af_packet: remove a stray tab in packet_set_ring() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:20 +0100
[PATCH 3.12 103/113] ipv6: simplify detection of first operational link-local address on interface Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:20 +0100
[PATCH 3.12 102/113] net: 6lowpan: fix lowpan_header_create non-compression memcpy call Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:20 +0100
[PATCH 3.12 109/113] net: filter: x86: fix JIT address randomization Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:20 +0100
[PATCH 3.12 065/113] vfs: fix uninitialized flags in splice_to_pipe() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 077/113] tty: serial: msm: Fix module autoload Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 063/113] l2tp: do not use udp_ioctl() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 068/113] futex: Move futex_init() to core_initcall Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 076/113] net: socket: fix recvmmsg not returning error from sock_error Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 080/113] USB: serial: ftdi_sio: fix modem-status error handling Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 090/113] ext4: validate s_first_meta_bg at mount time Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 088/113] rtlwifi: rtl_usb: Fix for URB leaking when doing ifconfig up/down Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 096/113] drm/nv50/disp: min/max are reversed in nv50_crtc_gamma_set() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 086/113] x86/platform/goldfish: Prevent unconditional loading Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 074/113] dccp: fix freeing skb too early for IPV6_RECVPKTINFO Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 075/113] irda: Fix lockdep annotations in hashbin_delete(). Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 082/113] USB: serial: ftdi_sio: fix line-status over-reporting Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 059/113] macvtap: read vnet_hdr_size once Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 091/113] ext4: fix fencepost in s_first_meta_bg validation Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 097/113] cpufreq: fix garbage kobjects on errors during suspend/resume Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 099/113] cpufreq: Clean up after a failing light-weight initialization Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 061/113] packet: round up linear to header len Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 081/113] USB: serial: ftdi_sio: fix extreme low-latency setting Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 070/113] rtc: interface: ignore expired timers when enqueuing new timers Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 060/113] sctp: avoid BUG_ON on sctp_wait_for_sndbuf Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 084/113] USB: serial: opticon: fix CTS retrieval at open Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 057/113] tcp: avoid infinite loop in tcp_splice_read() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 071/113] net/llc: avoid BUG_ON() in skb_orphan() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 079/113] USB: serial: cp210x: add new IDs for GE Bx50v3 boards Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 085/113] USB: serial: ark3116: fix register-accessor error handling Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 095/113] Staging: vt6655-6: potential NULL dereference in hostap_disable_hostapd() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 069/113] printk: use rcuidle console tracepoint Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 062/113] ping: fix a null pointer dereference Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 064/113] scsi: move the nr_phys_segments assert into scsi_init_io Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 072/113] packet: fix races in fanout_add() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 073/113] packet: Do not call fanout_release from atomic contexts Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 058/113] tun: read vnet_hdr_sz once Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 083/113] USB: serial: spcp8x5: fix modem-status handling Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 078/113] USB: serial: mos7840: fix another NULL-deref at open Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 087/113] goldfish: Sanitize the broken interrupt handler Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:30 +0100
[PATCH 3.12 023/113] USB: serial: option: add WeTelecom 0x6802 and 0x6803 products Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 037/113] USB: serial: option: add device ID for HP lt2523 (Novatel E371) Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 042/113] mac80211: Fix adding of mesh vendor IEs Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 050/113] ipv6: fix ip6_tnl_parse_tlv_enc_lim() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 034/113] USB: serial: qcserial: add Dell DW5570 QDL Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 055/113] netlabel: out of bound access in cipso_v4_validate() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 040/113] ARM: 8643/3: arm/ptrace: Preserve previous registers for short regset write Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 036/113] USB: Add quirk for WORLDE easykey.25 MIDI keyboard Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 041/113] target: Fix COMPARE_AND_WRITE ref leak for non GOOD status Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 051/113] ipv6: pointer math error in ip6_tnl_parse_tlv_enc_lim() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 054/113] ipv4: keep skb->dst around in presence of IP options Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 043/113] scsi: zfcp: fix use-after-free by not tracing WKA port open/close on failed send Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 067/113] scsi: don't BUG_ON() empty DMA transfers Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 026/113] drm/nouveau/nv1a,nv1f/disp: fix memory clock rate retrieval Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 022/113] USB: serial: option: add WeTelecom WM-D200 Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 053/113] net: use a work queue to defer net_disable_timestamp() work Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 029/113] svcrpc: fix oops in absence of krb5 module Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 033/113] can: bcm: fix hrtimer/tasklet termination in bcm op removal Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 066/113] siano: make it work again with CONFIG_VMAP_STACK Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 039/113] selinux: fix off-by-one in setprocattr Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 056/113] ip6_gre: fix ip6gre_err() invalid reads Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 049/113] can: Fix kernel panic at security_sock_rcv_skb Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 044/113] ALSA: seq: Fix race at creating a queue Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 035/113] USB: serial: pl2303: add ATEN device ID Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 032/113] mm, fs: check for fatal signals in do_generic_file_read() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 021/113] qmi_wwan/cdc_ether: add device ID for HP lt2523 (Novatel E371) WWAN card Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 031/113] mm/memory_hotplug.c: check start_pfn in test_pages_in_a_zone() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 025/113] USB: serial: option: add even more ZTE device ids Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 038/113] ARC: [arcompact] brown paper bag bug in unaligned access delay slot fixup Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 052/113] tcp: fix 0 divide in __tcp_select_window() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:40 +0100
[PATCH 3.12 007/113] ISDN: eicon: silence misleading array-bounds warning Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 012/113] nfs: Don't increment lock sequence ID after NFS4ERR_MOVED Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 011/113] parisc: Don't use BITS_PER_LONG in userspace-exported swab.h header Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 018/113] ipv6: addrconf: Avoid addrconf_disable_change() using RCU read-side lock Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 020/113] af_unix: move unix_mknod() out of bindlock Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 009/113] can: ti_hecc: add missing prepare and unprepare of the clock Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 016/113] platform/x86: intel_mid_powerbtn: Set IRQ_ONESHOT Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 008/113] can: c_can_pci: fix null-pointer-deref in c_can_start() - set device pointer Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 014/113] drm/i915: Don't leak edid in intel_crt_detect_ddc() Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 019/113] tcp: initialize max window for a new fastopen socket Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 015/113] s5k4ecgx: select CRC32 helper Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 003/113] net: possible use after free in dst_release Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 010/113] ARC: [arcompact] handle unaligned access delay slot corner case Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 013/113] SUNRPC: cleanup ida information when removing sunrpc module Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 017/113] net: fix harmonize_features() vs NETIF_F_HIGHDMA Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
[PATCH 3.12 002/113] crypto: caam - fix non-hmac hashes Jiri Slaby <jslaby@suse.cz> - 2017-03-06 10:50 +0100
Re: [PATCH 3.12 000/113] 3.12.71-stable review Guenter Roeck <linux@roeck-us.net> - 2017-03-06 15:50 +0100
Re: [PATCH 3.12 000/113] 3.12.71-stable review Jiri Slaby <jslaby@suse.cz> - 2017-03-09 21:00 +0100
Re: [PATCH 3.12 000/113] 3.12.71-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-03-06 20:30 +0100
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