Hello Jaroslav-san, Takashi-san,
Can you please reply your feedback for below mail chain.
Best regards,
Vanitha Channaiah
RBEI/ECF3
_____________________________________________
From: Channaiah Vanitha (RBEI/ECF3)
Sent: Tuesday, June 18, 2019 4:45 AM
To: 'Jaroslav Kysela' <perex@xxxxxxxx>; Takashi Iwai <tiwai@xxxxxxx>
Cc: Wischer Timo (ADITG/ESS) <twischer@xxxxxxxxxxxxxx>; alsa-devel@xxxxxxxxxxxxxxxx
Subject: RE: [PATCH v2 6/6] pcm: Update pcm->avail_min with needed_slave_avail_min, after reading unaligned frames
Hello Jaroslav-san, Takashi-san,
> Which hardware exactly? The hw_ptr should be reset when the streaming starts.
> It appears that the problem is specific to the direct plugins only when the period wakeups are a bit different than for the direct hardware access.
Firstly, sorry for late reply.
Issue is seen in RCar Kingfischer H3 es2.0 target.
The issue was seen during the below commit :
commit 07b7acb51d283d8469696c906b91f1882696a4d4
("ASoC: rsnd: update pointer more accurate")
https://patchwork.kernel.org/patch/9772671/
There could be a non-uniform jitter exists between when interrupt raised [rcar_dmac_isr_channel(), rcar_dmac_isr_channel_thread()]
and the interrupt is processed to read/calculate the DMA position [dma_set_residue()]
This could result in unaligned hw_ptr reported at user-space alsa lib.
Best regards,
Vanitha Channaiah
RBEI/ECF3
Tel. +91 80 6136-4436
-----Original Message-----
From: Jaroslav Kysela <mailto:perex@xxxxxxxx>
Sent: Thursday, May 16, 2019 11:05 PM
To: Channaiah Vanitha (RBEI/ECF3) <mailto:Vanitha.Channaiah@xxxxxxxxxxxx>; Takashi Iwai <mailto:tiwai@xxxxxxx>
Cc: Wischer Timo (ADITG/ESS) <mailto:twischer@xxxxxxxxxxxxxx>; mailto:alsa-devel@xxxxxxxxxxxxxxxx
Subject: Re: [PATCH v2 6/6] pcm: Update pcm->avail_min with needed_slave_avail_min, after reading unaligned frames
Dne 16. 05. 19 v 19:26 Channaiah Vanitha (RBEI/ECF3) napsal(a):
> Hello Takashi-san,
>
>> Can we avoid adding such a hack in the core code?
>> Basically the issue is very specific to direct-plugins, so this sort of workaround should be implemented locally there instead. I guess we can do similar tricks by overriding the calls in the callbacks.
>
> Issue can be seen without direct plugins too with involvement of only hw which reports unaligned hw ptr. As I have explained in below detailed description:
> "Also, this issue can be seen without dsnoop plugin, when HW reports unaligned hw_ptr For e.g. "
Which hardware exactly? The hw_ptr should be reset when the streaming starts.
It appears that the problem is specific to the direct plugins only when the period wakeups are a bit different than for the direct hardware access.
Jaroslav
--
Jaroslav Kysela <mailto:perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
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