linux-kernel - Re: [PATCH] ASoC: amd:Replacing MSI with Legacy IRQ model

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Date:   Tue, 22 Dec 2020 15:15:17 +0100
From:   Takashi Iwai <tiwai@...e.de>
To:     Ravulapati Vishnu vardhan rao 
        <Vishnuvardhanrao.Ravulapati@....com>
Cc:     <Alexander.Deucher@....com>, Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        "Takashi Iwai" <tiwai@...e.com>,
        Akshu Agrawal <akshu.agrawal@....com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        Vijendar Mukunda <Vijendar.Mukunda@....com>,
        "moderated list:SOUND - SOC LAYER / DYNAMIC AUDIO POWER MANAGEM..." 
        <alsa-devel@...a-project.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ASoC: amd:Replacing MSI with Legacy IRQ model

On Tue, 22 Dec 2020 12:59:18 +0100,
Ravulapati Vishnu vardhan rao wrote:
> 
> When we try to play and capture simultaneously we see that
> interrupts are genrated but our handler is not being acknowledged,
> After investigating further more in detail on this issue we found
> that IRQ delivery via MSI from the ACP IP is unreliable and so sometimes
> interrupt generated will not be acknowledged so MSI model shouldn't be used
> and using legacy IRQs will resolve interrupt handling issue.
> 
> This patch replaces MSI interrupt handling with legacy IRQ model.
> 
> Issue can be reproduced easily by running below python script:
> 
> import subprocess
> import time
> import threading
> 
> def do2():
>   cmd = 'aplay -f dat -D hw:2,1 /dev/zero -d 1'
>     subprocess.call(cmd, stdin=subprocess.PIPE,
> 			stderr=subprocess.PIPE, shell=True)
>     print('Play Done')
> 
> def run():
> 	for i in range(1000):
> 		do2()
> 
> def do(i):
>     cmd = 'arecord -f dat -D hw:2,2 /dev/null -d 1'
>     subprocess.call(cmd, stdout=subprocess.PIPE,
> 			stderr=subprocess.PIPE, shell=True)
>     print(datetime.datetime.now(), i)
> 
> t = threading.Thread(target=run)
> t.start()
> for i in range(1000):
> 	do(i)
> 
> t.join()
> 
> After applying this patch issue is resolved.
> 
> Signed-off-by: Ravulapati Vishnu vardhan rao <Vishnuvardhanrao.Ravulapati@....com>

Is this specific to Raven, i.e. Renoir doesn't need the same fix?
If so, it should be mentioned in the patch description.


thanks,

Takashi