[alsa-devel] [PATCH] ALSA: usb-audio: Assume first control interface is for audio
For devices with more than one control interface, let's assume the first one contains the audio controls. Unfortunately, there is no field in any of the descriptors to tell us whether a control interface is for audio or MIDI controls, so a better check is not easy to implement.
On a composite device with audio and MIDI functions, for example, the code currently overwrites chip->ctrl_intf, causing operations on the control interface to fail if they are issued after the device probe.
Signed-off-by: Daniel Mack daniel@caiaq.de --- sound/usb/card.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/sound/usb/card.c b/sound/usb/card.c index 9feb00c..b443a33 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -465,7 +465,13 @@ static void *snd_usb_audio_probe(struct usb_device *dev, goto __error; }
- chip->ctrl_intf = alts; + /* + * For devices with more than one control interface, we assume the + * first contains the audio controls. We might need a more specific + * check here in the future. + */ + if (!chip->ctrl_intf) + chip->ctrl_intf = alts;
if (err > 0) { /* create normal USB audio interfaces */
At Thu, 2 Sep 2010 17:13:15 +0800, Daniel Mack wrote:
For devices with more than one control interface, let's assume the first one contains the audio controls. Unfortunately, there is no field in any of the descriptors to tell us whether a control interface is for audio or MIDI controls, so a better check is not easy to implement.
On a composite device with audio and MIDI functions, for example, the code currently overwrites chip->ctrl_intf, causing operations on the control interface to fail if they are issued after the device probe.
Signed-off-by: Daniel Mack daniel@caiaq.de
Applied now. Thanks.
Takashi
sound/usb/card.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/sound/usb/card.c b/sound/usb/card.c index 9feb00c..b443a33 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -465,7 +465,13 @@ static void *snd_usb_audio_probe(struct usb_device *dev, goto __error; }
- chip->ctrl_intf = alts;
/*
* For devices with more than one control interface, we assume the* first contains the audio controls. We might need a more specific* check here in the future.*/if (!chip->ctrl_intf)
chip->ctrl_intf = alts;if (err > 0) { /* create normal USB audio interfaces */
-- 1.7.0.4
On Thu, Sep 02, 2010 at 11:59:18AM +0200, Takashi Iwai wrote:
At Thu, 2 Sep 2010 17:13:15 +0800, Daniel Mack wrote:
For devices with more than one control interface, let's assume the first one contains the audio controls. Unfortunately, there is no field in any of the descriptors to tell us whether a control interface is for audio or MIDI controls, so a better check is not easy to implement.
On a composite device with audio and MIDI functions, for example, the code currently overwrites chip->ctrl_intf, causing operations on the control interface to fail if they are issued after the device probe.
Signed-off-by: Daniel Mack daniel@caiaq.de
Applied now. Thanks.
This went upstream now, thanks. However, I forgot to mention in my commit log that we also need this backported to 2.6.35.
Greg, can you queue it up manually? Upstream commit is 7b6717e.
Thanks, Daniel
sound/usb/card.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/sound/usb/card.c b/sound/usb/card.c index 9feb00c..b443a33 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -465,7 +465,13 @@ static void *snd_usb_audio_probe(struct usb_device *dev, goto __error; }
- chip->ctrl_intf = alts;
/*
* For devices with more than one control interface, we assume the* first contains the audio controls. We might need a more specific* check here in the future.*/if (!chip->ctrl_intf)
chip->ctrl_intf = alts;if (err > 0) { /* create normal USB audio interfaces */
-- 1.7.0.4
On Fri, Sep 10, 2010 at 06:15:44PM +0200, Daniel Mack wrote:
On Thu, Sep 02, 2010 at 11:59:18AM +0200, Takashi Iwai wrote:
At Thu, 2 Sep 2010 17:13:15 +0800, Daniel Mack wrote:
For devices with more than one control interface, let's assume the first one contains the audio controls. Unfortunately, there is no field in any of the descriptors to tell us whether a control interface is for audio or MIDI controls, so a better check is not easy to implement.
On a composite device with audio and MIDI functions, for example, the code currently overwrites chip->ctrl_intf, causing operations on the control interface to fail if they are issued after the device probe.
Signed-off-by: Daniel Mack daniel@caiaq.de
Applied now. Thanks.
This went upstream now, thanks. However, I forgot to mention in my commit log that we also need this backported to 2.6.35.
Greg, can you queue it up manually? Upstream commit is 7b6717e.
Yes, I will do so, thanks for letting me know.
greg k-h
Thanks,
that's very useful for the mixer in the Fast Track Ultra!
Am 02.09.2010 11:13, schrieb Daniel Mack:
/*
* For devices with more than one control interface, we assume the* first contains the audio controls. We might need a more specific* check here in the future.*/if (!chip->ctrl_intf)
chip->ctrl_intf = alts;if (err> 0) { /* create normal USB audio interfaces */
participants (4)
-
Daniel Mack -
Felix Homann -
Greg KH -
Takashi Iwai