Hi All, On some boards setting power_save to a non 0 value leads to clicking / popping sounds when ever we enter/leave powersaving mode. Ideally we would figure out how to avoid these sounds, but that is not always feasible. This commit adds a blacklist for devices where powersaving is known to cause problems and disables it on these devices. Note this patch ATM is a RFC because I still need to get test-feedback that it actually works on affected boards. I tried to put this blacklist in userspace first: https://github.com/systemd/systemd/pull/8128 But the systemd maintainers rightfully pointed out that it would be impossible to then later remove entries once we actually find a way to make power-saving work on listed boards without issues. Having this list in the kernel will allow removal of the blacklist entry in the same commit which fixes the clicks / plops. I've chosen to also apply the blacklist to changes made through /sys/module/snd_hda_intel/parameters/power_save, since tools such as powertop and TLP do this automatically. About the choice to also apply this to changes made through /sys/module/snd_hda_intel/parameters/power_save, one could argue that this will get in the way of users who want the power-saving anyways and are willing to live with the clicks/plops. An alternative approach would be to only apply this to the value of the module-parameter at boot and then only when it matches CONFIG_SND_HDA_POWER_SAVE_DEFAULT. I'm open to changing this. Regards, Hans _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
