Re: [PATCH] ALSA: pcm: fix incorrect hw_base increase

[Jaroslav Kysela]

Dne 15. 05. 20 v 11:04 Lu, Brent napsal(a):
> > Is this a bugfix needed for older kernels as well?  When did this issue show
> > up?
> >
> > thanks,
> >
> > greg k-h
>
> It happens when DMA stop moving data from host to DSP/DAI for a long time
> (> half of buffer time). I know host driver should do something about it. But if
> not, the HWSYNC will keep increasing the hw_base and hw_ptr and confuses
> user space program.

I'm afraid, but with this code, you turn off the hw_ptr jiffies code. It would 
be better to fix the driver in this case (return the updated / estimated DMA 
pointer, increase DMA buffer size etc.). This "lag" is unacceptable.

						Jaroslav

> Regards,
> Brent


--
Jaroslav Kysela <perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.