[ 69/76] ALSA: hda - Stop LPIB delay counting on broken hardware

Greg Kroah-Hartman
2012-10-19T02:49:43Z

From: Takashi Iwai <tiwai@suse.de>

commit 1f04661fde9deda4a2cd5845258715a22d8af197 upstream.

If LPIB reports a pretty bad value, we can't trust such hardware for
calculating the PCM delay. Automatically turn off the delay counting
when such a problem is encountered.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=48911

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/pci/hda/hda_intel.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -2136,9 +2136,12 @@ static unsigned int azx_get_position(str
if (delay < 0)
delay += azx_dev->bufsize;
if (delay >= azx_dev->period_bytes) {
- snd_printdd("delay %d > period_bytes %d\n",
- delay, azx_dev->period_bytes);
- delay = 0; /* something is wrong */
+ snd_printk(KERN_WARNING SFX
+ "Unstable LPIB (%d >= %d); "
+ "disabling LPIB delay counting\n",
+ delay, azx_dev->period_bytes);
+ delay = 0;
+ chip->driver_caps &= ~AZX_DCAPS_COUNT_LPIB_DELAY;
}
azx_dev->substream->runtime->delay =
bytes_to_frames(azx_dev->substream->runtime, delay);