[alsa-devel] [PATCH] snd_interval_refine_first/last: exclude value only if also excluded before

[Takashi Iwai]

On Mon, 02 Jul 2018 16:53:06 +0200,
<twischer at de.adit-jv.com> wrote:
> 
> From: Timo Wischer <twischer at de.adit-jv.com>
> 
> Without this commit the following intervals [x y), (x y) were be
> replaced to (y-1 y) by snd_interval_refine_last(). This was also done if
> y-1 is part of the previous interval.
> With this changes it will be replaced with [y-1 y) in case of y-1 is
> part of the previous interval. A similar behavior will be used for
> snd_interval_refine_first().
> 
> This solves the issue reported here:
> https://bugzilla.opensuse.org/show_bug.cgi?id=1033179
> and work arounded with commit
> e736715 ("pcm: dmix: Disable var_periodsize as default").
> 
> I am able to reproduce the issue with a simplified aplay use case using
> the following configuration:
> pcm_slave.adr3_tdm_8ch {
>     pcm {
>         type hw
>         card "Loopback"
>         device 0
>     }
>     rate 48000
>     period_size 128
>     buffer_size 1024
>     channels 2
> }
> 
> pcm.dshare_Playback_3 {
>     type dmix
>     ipc_key 600
>     ipc_perm 0660
>     ipc_gid audio
>     var_periodsize true
>     slave adr3_tdm_8ch
> }
> 
> pcm.AdevAcousticoutSpeech {
>     type rate
>     slave.pcm dshare_Playback_3
>     slave.rate 48000
> }
> 
> $ modprobe snd_aloop
> $ aplay -v --period-size=352 -c2 -fS16_LE -r22500 -DAdevAcousticoutSpeech /dev/urandom
> ...
> Rule 9 (0xffff91d1f230): PERIODS=(0 2) -> NONE BUFFER_SIZE=480 PERIOD_SIZE=[240 240]
> refine_soft 'AdevAcousticoutSpeech' (end--22)
> ...
> aplay: ../../alsa-utils-1.1.5/aplay/aplay.c:1390: set_params: Assertion `err >= 0' failed.
> Aborted by signal Aborted...
> 
> The following stack trace shows where the -EINVAL will be thrown:
> __snd_pcm_hw_params_set_period_size_near()
> snd1_pcm_hw_param_set_near()
> snd1_pcm_hw_param_set_last()
> snd1_pcm_hw_refine_slave()
> snd1_pcm_hw_refine_soft()
> snd_pcm_hw_rule_div()
> snd1_interval_refine()
> 
> This issue exists due to PERIODS does not include 2
> Rule 9 (0xffff91d1f230): PERIODS=(0 9) -> (0 2) BUFFER_SIZE=[120 480]
> PERIOD_SIZE=(240 241)
> because of an invalid integer inverval of PERIOD_SIZE of (240 241).
> This interval is set by snd_interval_refine_last().
> 
> Signed-off-by: Timo Wischer <twischer at de.adit-jv.com>

Thanks for spotting this bug.  Applied now.

We need the similar fix in the kernel code, too...


Takashi