linux-kernel - Re: next-0519 on thinkpad x60: sound related? window manager crash

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Message-Id: <1592135950.lcpn6p9fh0.none@localhost>
Date:   Sun, 14 Jun 2020 08:07:48 -0400
From:   "Alex Xu (Hello71)" <alex_y_xu@...oo.ca>
To:     Takashi Iwai <tiwai@...e.de>
Cc:     alsa-devel@...a-project.org, bp@...en8.de, hch@...radead.org,
        Christoph Hellwig <hch@....de>, hpa@...or.com,
        linux-kernel@...r.kernel.org, mingo@...hat.com,
        Pavel Machek <pavel@....cz>, perex@...ex.cz,
        rientjes@...gle.com, tglx@...utronix.de, tiwai@...e.com,
        x86@...nel.org
Subject: Re: next-0519 on thinkpad x60: sound related? window manager crash

Excerpts from Takashi Iwai's message of June 14, 2020 5:54 am:
> On Sat, 13 Jun 2020 18:25:22 +0200,
> Alex Xu (Hello71) wrote:
>> 
>> Excerpts from Takashi Iwai's message of June 11, 2020 1:11 pm:
>> > Thanks, so something still missing in the mmap handling, I guess.
>> > 
>> > I've worked on two different branches for potential fixes of your
>> > problems.  Could you test topic/dma-fix and topic/dma-fix2 branches?
>> >   git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git
>> > Just pull one of them onto Linus' git HEAD.
>> > 
>> > I guess we'll go with David's new patch, but still it's interesting
>> > whether my changes do anything good actually.
>> > 
>> > 
>> > Takashi
>> > 
>> 
>> On torvalds 623f6dc593, topic/dma-fix causes sound to be output as 
>> alternating half-second bursts of noise and a few seconds of silence. 
>> topic/dma-fix2 appears to work properly.
> 
> OK, thanks for the feedback!  Just to make sure, you're using
> PulseAudio, right?
> If so, it was still something wrong about mmap, and the secondary
> method (the fallback to the continuous page) looks like a safer
> approach in the end.
> 
> I suppose that David's fix will be merged sooner or later.  Meanwhile
> I'll work on the change in the sound driver side to make things a bit
> more robust.  They don't conflict and both good applicable.
> 
> 
> thanks,
> 
> Takashi
> 

Ah, no, I think that wasn't clear. I use ALSA directly with mostly 
default configuration, except an asym sets separate default playback and 
record devices.

asound.conf:

defaults.pcm.card 1
defaults.ctl.card 1

pcm.!default {
    type asym
    playback.pcm
    {
        type plug
        slave.pcm "dmix"
    }
    capture.pcm
    {
        type plug
        slave.pcm {
            type dsnoop
            ipc_key 6793
            slave.pcm "hw:U0x46d0x81d"
        }
    }
}

I think I wasn't able to set defaults.pcm.dmix.card and 
defaults.pcm.dsnoop.card for some reason, not sure why. I can try that, 
but I don't think it will affect this mmap issue.

Thanks,
Alex.