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| author | Takashi Iwai <tiwai@suse.de> | 2016-04-29 12:49:04 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2016-04-29 12:49:04 +0300 |
| commit | 57dd5414a087991d427067b32dc3324af61b1c8b (patch) | |
| tree | 2ce444fa16975ba689ca7271e513c66cef58a3b2 /sound/usb/clock.c | |
| parent | a33d59599653edc6469c582f0ffd99c5fc58af04 (diff) | |
| download | linux-57dd5414a087991d427067b32dc3324af61b1c8b.tar.xz | |
ALSA: usb-audio: Limit retrying sample rate reads
There are many USB audio devices with buggy firmware that don't react
with the sample rate reading properly. This often results in the
flood of error messages and slowing down the operation.
The sample rate read back is basically only for confirming the sample
rate setup, and it's not critically important. As a compromise, in
this patch, we stop the sample rate read back once when the device
gives errors more than tolerance (twice, as of now). This should
improve most of error cases while we still can catch the firmware
bugginess.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/clock.c')
| -rw-r--r-- | sound/usb/clock.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/sound/usb/clock.c b/sound/usb/clock.c index 7ccbcaf6a147..26dd5f20f149 100644 --- a/sound/usb/clock.c +++ b/sound/usb/clock.c @@ -309,6 +309,9 @@ static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface, * support reading */ if (snd_usb_get_sample_rate_quirk(chip)) return 0; + /* the firmware is likely buggy, don't repeat to fail too many times */ + if (chip->sample_rate_read_error > 2) + return 0; if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR, USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN, @@ -316,6 +319,7 @@ static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface, data, sizeof(data))) < 0) { dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n", iface, fmt->altsetting, ep); + chip->sample_rate_read_error++; return 0; /* some devices don't support reading */ } |