Re: [PATCH] ALSA: usb-audio: Explicitly set up the clock selector

Thanks, Dr. Iwai!

I haven't tested the finalized patch yet, but I'll give it a shot on top of 5.12-rc7. Should be OK, nevertheless thorough testing is always a good idea.

Regards, Geraldo

Em Ter, 13 de abr de 2021 05:41, Takashi Iwai tiwai@suse.de escreveu:

In the current code, we have some assumption that the audio clock selector has been set up implicitly and don't want to touch it unless it's really needed for the fallback autoclock setup. This works for most devices but some seem having a problem. Partially this was covered for the devices with a single connector at the initialization phase (commit 086b957cc17f "ALSA: usb-audio: Skip the clock selector inquiry for single connections"), but also there are cases where the wrong clock set up is kept silently. The latter seems to be the cause of the noises on Behringer devices.

In this patch, we explicitly set up the audio clock selector whenever the appropriate node is found.

Reported-by: Geraldo Nascimento geraldogabriel@gmail.com BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199327 Link: https://lore.kernel.org/r/CAEsQvcvF7LnO8PxyyCxuRCx=7jNeSCvFAd-+dE0g_rd1rOxxd... Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de

---

sound/usb/clock.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/sound/usb/clock.c b/sound/usb/clock.c index a746802d0ac3..17bbde73d4d1 100644 --- a/sound/usb/clock.c +++ b/sound/usb/clock.c @@ -296,7 +296,7 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,

    selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
    if (selector) {

•           int ret, i, cur;
  

•           int ret, i, cur, err;
  
            if (selector->bNrInPins == 1) {
                    ret = 1;
  

@@ -324,13 +324,17 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip, ret = __uac_clock_find_source(chip, fmt, selector->baCSourceID[ret - 1], visited, validate);

•           if (ret > 0) {
  

•                   err = uac_clock_selector_set_val(chip, entity_id,
  

cur);

•                   if (err < 0)
  

•                           return err;
  

•           }
  

•           if (!validate || ret > 0 || !chip->autoclock)
                    return ret;
  
            /* The current clock source is invalid, try others. */
            for (i = 1; i <= selector->bNrInPins; i++) {
  

•                   int err;
  

•                   if (i == cur)
                            continue;
  
  

@@ -396,7 +400,7 @@ static int __uac3_clock_find_source(struct snd_usb_audio *chip,

    selector = snd_usb_find_clock_selector_v3(chip->ctrl_intf,

entity_id); if (selector) {

•           int ret, i, cur;
  

•           int ret, i, cur, err;
  
            /* the entity ID we are looking for is a selector.
             * find out what it currently selects */
  

@@ -418,6 +422,12 @@ static int __uac3_clock_find_source(struct snd_usb_audio *chip, ret = __uac3_clock_find_source(chip, fmt, selector->baCSourceID[ret - 1], visited, validate);

•           if (ret > 0) {
  

•                   err = uac_clock_selector_set_val(chip, entity_id,
  

cur);

•                   if (err < 0)
  

•                           return err;
  

•           }
  

•           if (!validate || ret > 0 || !chip->autoclock)
                    return ret;
  
  

-- 2.26.2