ALSA: cmipci: work around invalid PCM pointer
authorClemens Ladisch <clemens@ladisch.de>
Wed, 24 Mar 2010 06:10:54 +0000 (07:10 +0100)
committerTakashi Iwai <tiwai@suse.de>
Wed, 24 Mar 2010 07:02:11 +0000 (08:02 +0100)
commit1c583063a5c769fe2ec604752e383972c69e6d9b
tree566f530439c23f25b448f7e8c6b576bc3f443fdd
parentfc8aa7b16a5fcfe9c6d0be9bb587f1fcedd9145f
ALSA: cmipci: work around invalid PCM pointer

When the CMI8738 FRAME2 register is read, the chip sometimes (probably
when wrapping around) returns an invalid value that would be outside the
programmed DMA buffer. This leads to an inconsistent PCM pointer that is
likely to result in an underrun.

To work around this, read the register multiple times until we get a
valid value; the error state seems to be very short-lived.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Reported-and-tested-by: Matija Nalis <mnalis-alsadev@voyager.hr>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
sound/pci/cmipci.c