[alsa-devel] [PATCH bugfix v3.4] ALSA: hda - fix "silence after S3" regression
Konstantin Khlebnikov
khlebnikov at openvz.org
Tue May 8 15:38:45 CEST 2012
Takashi Iwai wrote:
> At Tue, 08 May 2012 17:08:10 +0400,
> Konstantin Khlebnikov wrote:
>>
>> This fixes regression in shd-hda-codec after 785f857d1cb0856b612b46a0545b74aa2
>> ("ALSA: hda - Set codec to D3 forcibly even if not used")
>>
>> hda_set_power_state() call must be explicitly protected against recursive
>> snd_hda_power_up/down() calls, otherwise it accidentally switches device into
>> D0 right before suspend. As result after resume sound device stays in D3 state
>> and does not works because driver believes that the device is on already.
>>
>> Signed-off-by: Konstantin Khlebnikov<khlebnikov at openvz.org>
>
> Hrm, does this really fix your problem? The path is called only
> during the suspend. Then, in the resume path, the codec is all
> powered up anyway.
This fixes my problem: during suspend hda_set_power_state() calls snd_hda_power_up()
it set codec->power_on = 1 and switches device into D0. At S3 resume codec->power_on == 1
but all devices actually in D3 state. As result on resume path device stays in D3,
but after one power-save cycle all works again.
>
> If the race between the leftover power-save work is really a culprit,
> the fix would be just calling cancel_delayed_work_sync() before
> that point...
Race was always there, my problem was caused by commit which mentioned above.
Whole this code is very racy, someone needs to fix it.
>
>
> thanks,
>
> Takashi
>
>> ---
>> sound/pci/hda/hda_codec.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
>> index 7a8fcc4..a0ea9d6 100644
>> --- a/sound/pci/hda/hda_codec.c
>> +++ b/sound/pci/hda/hda_codec.c
>> @@ -5444,10 +5444,14 @@ int snd_hda_suspend(struct hda_bus *bus)
>> list_for_each_entry(codec,&bus->codec_list, list) {
>> if (hda_codec_is_power_on(codec))
>> hda_call_codec_suspend(codec);
>> - else /* forcibly change the power to D3 even if not used */
>> + else {
>> + /* forcibly change the power to D3 even if not used */
>> + codec->power_transition = 1;
>> hda_set_power_state(codec,
>> codec->afg ? codec->afg : codec->mfg,
>> AC_PWRST_D3);
>> + codec->power_transition = 0;
>> + }
>> if (codec->patch_ops.post_suspend)
>> codec->patch_ops.post_suspend(codec);
>> }
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
More information about the Alsa-devel
mailing list