Well, I tried and it works perfectly for me - but I don't use kernel modules for sound. If you have modules loading it with the appropiate options will surely make powersaving work without problems, but in my case it's necessary to set the parameter via sysfs and play a sound afterwards - playing a sound means to open the /dev/dsp device technically and as I already said, my workaround works nicely for me.
Peter On Wed, 2007-05-23 at 14:53 +0200, Alexey Fisher wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > This work around not working for me. > > It seems sysfs options for snd_ac97_codec true only for new devices. > It's mean you need reload snd_card_driver to make youse of this changes > or just > echo "options snd_ac97_codec power_save=1" >> /etc/modprobe.d/options > > this working for me well. > i don't think this is a bug, the same is for usb_core/autosuspend this > working only for new devices too. Only difference is that every sysfs > usb_device have this options but not sound_devices. > > power_save options is experimental and disabled default, so a leak of > explanation in kernel or on powertop webseite is the problem. > > Alexey Fisher > > > Peter Ganzhorn wrote: > > I got an idea for a possible workaround until this issue is fixed: > > If using the sysfs interface to set the powermanagement of AC97, you > > will most probably set it in an init script, I did in /etc/rc.local . > > After you set the value to "Y" (or "1"), you need to play a sound once > > to trigger the power suspend - so why not add a second line to your init > > script: > > > > echo "0" > /dev/dsp > > > > I haven't tested if this really works in the init script, but when I do > > this, I can hear the typical power-resume clicking noise throught my > > speakers. > > So for the driver a sound was played and hence the device should be > > suspended afterwards when the autosuspend parameter is set. > > If anyone tries this at startup before me let me know if this trick > > works, but I'm confident this should do as a workaround for now. > > > > Peter Ganzhorn > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.6 (GNU/Linux) > > iD8DBQFGVDlRVVCoNUmKuAcRAnWFAJ4sPhgeA1xnNToKJ21oI2qHM25lYQCbBMwq > zrDjuTJkZ+8iwvdxQzNaXOY= > =9gtL > -----END PGP SIGNATURE----- _______________________________________________ Power mailing list [email protected] http://www.bughost.org/mailman/listinfo/power
