From 0191a2a28cdc34a57fee2c027c101a023f9a61f9 Mon Sep 17 00:00:00 2001 From: Frank Schaefer Date: Mon, 13 Jan 2014 19:02:07 -0300 Subject: [PATCH] [media] em28xx: fix check for audio only usb interfaces when changing the usb alternate setting MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Previously, we've been assuming that the video endpoints are always at usb interface 0. Hence, if vendor audio endpoints are provided at a separate interface, they were supposed to be at interface number > 0. Instead of checking for (interface number > 0) to determine if an interface is a pure audio interface, dev->is_audio_only should be checked. Signed-off-by: Frank Schäfer Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/em28xx/em28xx-audio.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/media/usb/em28xx/em28xx-audio.c b/drivers/media/usb/em28xx/em28xx-audio.c index 50c4ab49a276..332abf7b32f8 100644 --- a/drivers/media/usb/em28xx/em28xx-audio.c +++ b/drivers/media/usb/em28xx/em28xx-audio.c @@ -266,7 +266,7 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream) dprintk("opening device and trying to acquire exclusive lock\n"); runtime->hw = snd_em28xx_hw_capture; - if ((dev->alt == 0 || dev->ifnum) && dev->adev.users == 0) { + if ((dev->alt == 0 || dev->is_audio_only) && dev->adev.users == 0) { int nonblock = !!(substream->f_flags & O_NONBLOCK); if (nonblock) { @@ -274,10 +274,21 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream) return -EAGAIN; } else mutex_lock(&dev->lock); - if (dev->ifnum) + if (dev->is_audio_only) + /* vendor audio is on a separate interface */ dev->alt = 1; else + /* vendor audio is on the same interface as video */ dev->alt = 7; + /* + * FIXME: The intention seems to be to select the alt + * setting with the largest wMaxPacketSize for the video + * endpoint. + * At least dev->alt should be used instead, but we + * should probably not touch it at all if it is + * already >0, because wMaxPacketSize of the audio + * endpoints seems to be the same for all. + */ dprintk("changing alternate number on interface %d to %d\n", dev->ifnum, dev->alt);