Openmoko Bug #2478: linux 2.6.39: alsa state not correctly restored in resume

[Openmoko Public Trac]

#2478: linux 2.6.39: alsa state not correctly restored in resume
---------------------+------------------------------------------------------
 Reporter:  lindi    |          Owner:  openmoko-kernel                        
     Type:  defect   |         Status:  new                                    
 Priority:  high     |      Milestone:                                         
Component:  kernel   |        Version:                                         
 Severity:  blocker  |       Keywords:  kernel alsa suspend resume linux 2.6.39
 Haspatch:  0        |      Blockedby:                                         
Estimated:           |    Patchreview:                                         
 Blocking:           |   Reproducible:  always                                 
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Comment(by lindi):

 {{{
 lindi at ginger:~$ stap -v -e 'probe
 module("snd_soc_core").statement("snd_soc_suspend@/home/lindi/debian
 /debian-
 linux-2.6/linux-2.6-2.6.39/debian/build/source_armel_none/sound/soc/soc-
 core.c:1126") { printf("%s %d %x %d\n", pp(), $codec->suspended,
 $codec->driver->suspend, $codec->dapm->bias_level); }'
 Pass 1: parsed user script and 74 library script(s) using
 21340virt/12972res/2156shr kb, in 4090usr/290sys/4378real ms.
 Pass 2: analyzed script: 1 probe(s), 4 function(s), 3 embed(s), 0
 global(s) using 62840virt/14988res/3020shr kb, in 500usr/430sys/1482real
 ms.
 Pass 3: translated to C into
 "/tmp/stapXzhuo1/stap_a0b7707bb6646bdaa8e34301146c98da_4336.c" using
 63748virt/16496res/4084shr kb, in 990usr/210sys/1208real ms.
 Pass 4: compiled C into "stap_a0b7707bb6646bdaa8e34301146c98da_4336.ko" in
 52030usr/6460sys/58859real ms.
 Pass 5: starting run.
 module("snd_soc_core").statement("snd_soc_suspend@/home/lindi/debian
 /debian-
 linux-2.6/linux-2.6-2.6.39/debian/build/source_armel_none/sound/soc/soc-
 core.c:1127") 0 0 0
 module("snd_soc_core").statement("snd_soc_suspend@/home/lindi/debian
 /debian-
 linux-2.6/linux-2.6-2.6.39/debian/build/source_armel_none/sound/soc/soc-
 core.c:1127") 0 bf09088c 3
 }}}

 shows that we have two codecs.

 The first one has no ".suspend".

 The second one has ".suspend" but its "dapm.bias_level" is set to 3 which
 is SND_SOC_BIAS_ON. This means that the codec->driver->suspend(codec,
 PMSG_SUSPEND); line is not executed and I guess same goes also for
 codec->driver->resume(codec);.

 If I change bias_level to SND_SOC_BIAS_OFF using

 {{{
 #!/usr/bin/stap

 probe module("snd_soc_core").statement("snd_soc_suspend@/home/lindi/debian
 /debian-
 linux-2.6/linux-2.6-2.6.39/debian/build/source_armel_none/sound/soc/soc-
 core.c:1126") {
   if ($codec->dapm->bias_level == 3) {
     $codec->dapm->bias_level = 0;
   }
 }

 probe module("snd_soc_wm8753").function("wm8753_suspend") {
   printf("%s\n", pp());
 }

 probe module("snd_soc_wm8753").function("wm8753_resume") {
   printf("%s\n", pp());
 }

 }}}

 then wm8753_suspend and wm8753_resume are called and speaker-test works!

-- 
Ticket URL: <https://docs.openmoko.org/trac/ticket/2478#comment:3>
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