[alsa-devel] [PATCH - dmix v5 1/1] pcm: dmix: Add option to allow alignment of slave pointers

[Takashi Iwai]

On Tue, 13 Nov 2018 08:43:00 +0100,
<twischer at de.adit-jv.com> wrote:
> 
> From: Laxmi Devi <Laxmi.Devi at in.bosch.com>
> 
> These changes are required due to the kernel
> commit 07b7acb51d283d8469696c906b91f1882696a4d4
> ("ASoC: rsnd: update pointer more accurate")
> 
> Issue is that snd_pcm_wait() goes back to waiting because the hw_ptr
> is not period aligned. Therefore snd_pcm_wait() will block for a longer
> time as required.
> 
> With these rcar driver changes the exact position of the dma is returned.
> During snd_pcm_start they read hw_ptr as reference, and this hw_ptr
> is now not period aligned, and is a little ahead over the period while it
> is read. Therefore when the avail is calculated during snd_pcm_wait(),
> it is missing the avail_min by a few frames.
> 
> An additional option hw_ptr_alignment is provided to dmix configuration,
> to allow the user to configure the slave application and hw pointer
> alignment at startup
> 
> 
> Signed-off-by: Laxmi Devi <Laxmi.Devi at in.bosch.com>
> Signed-off-by: Timo Wischer <twischer at de.adit-jv.com>

Thanks, applied now with minor fixes (mostly spaces and line breaks).


Takashi