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Groups > linux.kernel > #1651446 > unrolled thread
| Started by | Julian Scheel <julian@jusst.de> |
|---|---|
| First post | 2017-05-26 18:00 +0200 |
| Last post | 2017-05-30 02:10 +0200 |
| Articles | 2 — 2 participants |
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Re: [PATCH v4 3/3] usb: gadget: add f_uac1 variant based on a new u_audio api Julian Scheel <julian@jusst.de> - 2017-05-26 18:00 +0200
Re: [PATCH v4 3/3] usb: gadget: add f_uac1 variant based on a new u_audio api Ruslan Bilovol <ruslan.bilovol@gmail.com> - 2017-05-30 02:10 +0200
| From | Julian Scheel <julian@jusst.de> |
|---|---|
| Date | 2017-05-26 18:00 +0200 |
| Subject | Re: [PATCH v4 3/3] usb: gadget: add f_uac1 variant based on a new u_audio api |
| Message-ID | <tLpOF-7Ks-7@gated-at.bofh.it> |
On 18.05.2017 00:37, Ruslan Bilovol wrote: > This patch adds a new function 'f_uac1_acard' > (f_uac1 with virtual "ALSA card") that > uses recently created u_audio API. Comparing > to legacy f_uac1 function implementation it > doesn't require any real Audio codec to be > present on the device. In f_uac1_acard audio > streams are simply sinked to and sourced > from a virtual ALSA sound card created > using u_audio API. > > Legacy f_uac1 approach is to write audio > samples directly to existing ALSA sound > card > > f_uac1_acard approach is more generic/flexible > one - create an ALSA sound card that > represents USB Audio function and allows to > be used by userspace application that > may choose to do whatever it wants with the > data received from the USB Host and choose > to provide whatever it wants as audio data > to the USB Host. > > f_uac1_acard also has capture support (gadget->host) > thanks to easy implementation via u_audio. > By default, capture interface has 48000kHz/2ch > configuration, same as playback channel has. > > f_uac1_acard descriptors naming convention > uses f_uac2 driver naming convention that > makes it more common and meaningful. > > Comparing to f_uac1, the f_uac1_acard doesn't > have volume/mute functionality. This is because > the f_uac1 volume/mute feature unit was dummy > implementation since that driver creation (2009) > and never had any real volume control or mute > functionality, so there is no any difference > here. > > Since f_uac1_acard functionality, exposed > interface to userspace (virtual ALSA card), > input parameters are so different comparing > to legace f_uac1, that there is no any > reason to keep them in the same file/module, > and separate function was created. > > g_audio can be built using one of existing > UAC functions (f_uac1, f_uac1_acard or f_uac2) > > Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com> > --- > .../ABI/testing/configfs-usb-gadget-uac1_acard | 14 + > Documentation/usb/gadget-testing.txt | 45 ++ > drivers/usb/gadget/Kconfig | 21 + > drivers/usb/gadget/function/Makefile | 2 + > drivers/usb/gadget/function/f_uac1_acard.c | 803 +++++++++++++++++++++ > drivers/usb/gadget/function/u_uac1_acard.h | 41 ++ > drivers/usb/gadget/legacy/Kconfig | 15 +- > drivers/usb/gadget/legacy/audio.c | 53 ++ > 8 files changed, 992 insertions(+), 2 deletions(-) > create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-uac1_acard > create mode 100644 drivers/usb/gadget/function/f_uac1_acard.c > create mode 100644 drivers/usb/gadget/function/u_uac1_acard.h > Tested on iMX7D using chipidea usb gadget controller. Tested Windows 10 and Linux 4.11 as host. Both work fine. Tested-by: Julian Scheel <julian@jusst.de>
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| From | Ruslan Bilovol <ruslan.bilovol@gmail.com> |
|---|---|
| Date | 2017-05-30 02:10 +0200 |
| Message-ID | <tMCTw-7FU-3@gated-at.bofh.it> |
| In reply to | #1651446 |
On Fri, May 26, 2017 at 6:52 PM, Julian Scheel <julian@jusst.de> wrote: > On 18.05.2017 00:37, Ruslan Bilovol wrote: >> >> This patch adds a new function 'f_uac1_acard' >> (f_uac1 with virtual "ALSA card") that >> uses recently created u_audio API. Comparing >> to legacy f_uac1 function implementation it >> doesn't require any real Audio codec to be >> present on the device. In f_uac1_acard audio >> streams are simply sinked to and sourced >> from a virtual ALSA sound card created >> using u_audio API. >> >> Legacy f_uac1 approach is to write audio >> samples directly to existing ALSA sound >> card >> >> f_uac1_acard approach is more generic/flexible >> one - create an ALSA sound card that >> represents USB Audio function and allows to >> be used by userspace application that >> may choose to do whatever it wants with the >> data received from the USB Host and choose >> to provide whatever it wants as audio data >> to the USB Host. >> >> f_uac1_acard also has capture support (gadget->host) >> thanks to easy implementation via u_audio. >> By default, capture interface has 48000kHz/2ch >> configuration, same as playback channel has. >> >> f_uac1_acard descriptors naming convention >> uses f_uac2 driver naming convention that >> makes it more common and meaningful. >> >> Comparing to f_uac1, the f_uac1_acard doesn't >> have volume/mute functionality. This is because >> the f_uac1 volume/mute feature unit was dummy >> implementation since that driver creation (2009) >> and never had any real volume control or mute >> functionality, so there is no any difference >> here. >> >> Since f_uac1_acard functionality, exposed >> interface to userspace (virtual ALSA card), >> input parameters are so different comparing >> to legace f_uac1, that there is no any >> reason to keep them in the same file/module, >> and separate function was created. >> >> g_audio can be built using one of existing >> UAC functions (f_uac1, f_uac1_acard or f_uac2) >> >> Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com> >> --- >> .../ABI/testing/configfs-usb-gadget-uac1_acard | 14 + >> Documentation/usb/gadget-testing.txt | 45 ++ >> drivers/usb/gadget/Kconfig | 21 + >> drivers/usb/gadget/function/Makefile | 2 + >> drivers/usb/gadget/function/f_uac1_acard.c | 803 >> +++++++++++++++++++++ >> drivers/usb/gadget/function/u_uac1_acard.h | 41 ++ >> drivers/usb/gadget/legacy/Kconfig | 15 +- >> drivers/usb/gadget/legacy/audio.c | 53 ++ >> 8 files changed, 992 insertions(+), 2 deletions(-) >> create mode 100644 >> Documentation/ABI/testing/configfs-usb-gadget-uac1_acard >> create mode 100644 drivers/usb/gadget/function/f_uac1_acard.c >> create mode 100644 drivers/usb/gadget/function/u_uac1_acard.h >> > > Tested on iMX7D using chipidea usb gadget controller. Tested Windows 10 and > Linux 4.11 as host. Both work fine. > > Tested-by: Julian Scheel <julian@jusst.de> Thanks for testing it. I'll wait for additional reviews/comments next few days and than will send new patchset with addressed comments. Also current patchset have minor conflict when applied on top of Felipe's testing/next branch which is moved to 4.12-rc1. I've resolved conflict but did only build test so far. Anyway I uploaded rebased patches to github [1] if anybody wants to try them. [1] https://github.com/rbilovol/kernel/commits/usbaudio-v4.12-balbi-testing-next Best regards, Ruslan
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