Bug#531090: Discovery: BIOS resume initialises soundcard, while uswsusp resume fails

[Friedrich Delgado <friedel@nomaden.org>]

Package: linux-image-2.6.32-5-486
Severity: normal

I've made an interesting discovery today, when playing with the
libretto again:

 - linux-image-2.6.32-5-486 contains an apm.ko kernel module, which I
    was able to insert in my ramdisk, but unfortunately it fails to
    load (different bug, but in case it's interesting:

    "error inserting apm.ko no such device" on console and
    "apm: BIOS not found" in dmesg)

 - when I disable acpi explicitly, the kernel is not able to switch
   off the laptop any more, but then I get my power-off button back to
   do the on-board BIOS hibernate

 - When I hibernate with the BIOS, I can remove all sound drivers and
   then load them again with modprobe snd_opl3sa2 and I'm able to play
   sound!

 - When I try the same with s2disk: no sound, hanging application

 - Fun: After failing to load the sound driver with s2disk, doing BIOS
   hibernation and then reloading fixes sound

My conjecture from this is that the BIOS hibernation ensures the sound
card is properly initialized after resume, but no idea why it fails
with s2disk. Since no acpi *or* apm drivers are loaded, I guess the kernel
doesn't have the slightest idea of what's happening during BIOS
hibernate/resume (at least there's nothing at all in syslog).

Now if I could load my apm module, I could ensure the snd modules get
unloaded when I hibernate and reloaded on resume, since the BIOS
hibernation is not compatible with acpi (iirc the libretto only has an
extremely early and basic acpi implementation).

Or (what this bug is really about): If the opl3sa2 driver could
properly initialize the sound card, I'd be happy (with s2disk and/or
acpi) too. (Even though s2disk is considerably slower than BIOS
hibernation.)

-- System Information:
Debian Release: squeeze/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'karmic'), (500, 'unstable'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-5-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.utf8, LC_CTYPE=de_DE.utf8 (charmap=UTF-8) (ignored: LC_ALL set to de_DE.utf8)
Shell: /bin/sh linked to /bin/bash

-- 
Dipl.-Inform. Friedrich Delgado <delgado@pre-sense.de>

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