| Message ID | 20180710202743.69639-1-agoode@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 10 Jul 2018 22:27:43 +0200, Adam Goode wrote: > > If the audio device is externally clocked and set to a rate that does > not match the external clock, the clock will never be valid and we cannot > set the rate successfully. To fix this, allow a rate change even if > the clock is initially invalid, and validate again after the rate is > changed. > > This fixes problems with MOTU UltraLite AVB hardware over USB. > > Signed-off-by: Adam Goode <agoode@google.com> The logic looks good, but just a few minor nitpicking below. > diff --git a/sound/usb/clock.c b/sound/usb/clock.c > index c79749613fa6..9e9019464f91 100644 > --- a/sound/usb/clock.c > +++ b/sound/usb/clock.c > @@ -513,14 +513,26 @@ static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface, > bool writeable; > u32 bmControls; > > + /* First, try to find a valid clock. This may trigger > + * automatic clock selection if the current clock is not > + * valid. */ The "*/" should put in another line. > clock = snd_usb_clock_find_source(chip, fmt->protocol, > fmt->clock, true); > - if (clock < 0) > - return clock; > + if (clock < 0) { > + /* We did not find a valid clock, but that might be > + * because the current sample rate does not match an > + * external clock source. Try again without validation > + * and we will do another validation after setting the > + * rate. */ Ditto. > + clock = snd_usb_clock_find_source(chip, fmt->protocol, > + fmt->clock, false); > + if (clock < 0) > + return clock; > + } > > prev_rate = get_sample_rate_v2v3(chip, iface, fmt->altsetting, clock); > if (prev_rate == rate) > - return 0; > + return uac_clock_source_is_valid(chip, fmt->protocol, clock) ? 0 : -ENXIO; It's better to have a single return path, so let's use here "goto validation", and... > if (fmt->protocol == UAC_VERSION_3) { > struct uac3_clock_source_descriptor *cs_desc; > @@ -577,7 +589,8 @@ static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface, > snd_usb_set_interface_quirk(dev); > } > > - return 0; > + /* validate clock after rate change */ > + return uac_clock_source_is_valid(chip, fmt->protocol, clock) ? 0 : -ENXIO; ... put here like validation: if (!uac_clock_source_is_valid(chip, fmt->protocol, clock)) return -ENXIO; return 0; thanks, Takashi
diff --git a/sound/usb/clock.c b/sound/usb/clock.c index c79749613fa6..9e9019464f91 100644 --- a/sound/usb/clock.c +++ b/sound/usb/clock.c @@ -513,14 +513,26 @@ static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface, bool writeable; u32 bmControls; + /* First, try to find a valid clock. This may trigger + * automatic clock selection if the current clock is not + * valid. */ clock = snd_usb_clock_find_source(chip, fmt->protocol, fmt->clock, true); - if (clock < 0) - return clock; + if (clock < 0) { + /* We did not find a valid clock, but that might be + * because the current sample rate does not match an + * external clock source. Try again without validation + * and we will do another validation after setting the + * rate. */ + clock = snd_usb_clock_find_source(chip, fmt->protocol, + fmt->clock, false); + if (clock < 0) + return clock; + } prev_rate = get_sample_rate_v2v3(chip, iface, fmt->altsetting, clock); if (prev_rate == rate) - return 0; + return uac_clock_source_is_valid(chip, fmt->protocol, clock) ? 0 : -ENXIO; if (fmt->protocol == UAC_VERSION_3) { struct uac3_clock_source_descriptor *cs_desc; @@ -577,7 +589,8 @@ static int set_sample_rate_v2v3(struct snd_usb_audio *chip, int iface, snd_usb_set_interface_quirk(dev); } - return 0; + /* validate clock after rate change */ + return uac_clock_source_is_valid(chip, fmt->protocol, clock) ? 0 : -ENXIO; } int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
If the audio device is externally clocked and set to a rate that does not match the external clock, the clock will never be valid and we cannot set the rate successfully. To fix this, allow a rate change even if the clock is initially invalid, and validate again after the rate is changed. This fixes problems with MOTU UltraLite AVB hardware over USB. Signed-off-by: Adam Goode <agoode@google.com>