ALSA: hda - Fix DMA position inaccuracy

ALSA: hda - Fix DMA position inaccuracy

commit 9ad593f6d326e7a4664e3856520f6c042f82a37f upstream

Many HD-audio controllers seem inaccurate about the IRQ timing of
PCM period updates.  This has caused problems on audio quality; e.g.
JACK doesn't work with two periods.

This patch fixes the problem by checking the current DMA position
at IRQ handler and delays the period-update via a workq if it's
inaccurate.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>