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 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.
The blacklist only applies to the default power_save module-option value,
if a user explicitly sets the module-option then the blacklist is not
used.
[ added an ifdef CONFIG_PM for the build error -- tiwai]
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1525104
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=198611
Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
1ba8f9d308