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

Greg Kroah-Hartman
2020-05-15T07:04:50Z

On Fri, May 15, 2020 at 12:09:39PM +0800, Brent Lu wrote:
> The hw_base will be increased by runtime->buffer_size frames
> unconditionally if the runtime->status->hw_ptr is not updated for over
> half of buffer time. As the hw_base increases, so does the
> runtime->status->hw_ptr which could lead to invalid return value when
> user space program calls snd_pcm_avail() function.
>
> By updating runtime->hw_ptr_jiffies each time the HWSYNC is called,
> the hw_base will keep the same when buffer stall happens, so does the
> hw_ptr.
>
> Signed-off-by: Brent Lu <brent.lu@intel.com>
> ---
> sound/core/pcm_lib.c | 1 +
> 1 file changed, 1 insertion(+)

Is this a bugfix needed for older kernels as well? When did this issue
show up?

thanks,

greg k-h