From: Takashi Iwai tiwai@suse.de
commit c2c3657f0aedb8736a0fb7b2b1985adfb86e7802 upstream.
It's been reported that, when neither nouveau nor Nvidia graphics driver is used, the screen starts flickering. And, after comparing between the working case (stable 4.4.x) and the broken case, it turned out that the problem comes from the audio component binding. The Nvidia and AMD audio binding code clears the bus->keep_power flag whenever snd_hdac_acomp_init() succeeds. But this doesn't mean that the component is actually bound, but it merely indicates that it's ready for binding. So, when both nouveau and Nvidia are blacklisted or not ready, the driver keeps running without the audio component but also with bus->keep_power = false. This made the driver runtime PM kicked in and powering down when unused, which results in flickering in the graphics side, as it seems.
For fixing the bug, this patch moves the bus->keep_power flag change into generic_acomp_notifier_set() that is the function called from the master_bind callback of component ops; i.e. it's guaranteed that the binding succeeded.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208609 Fixes: 5a858e79c911 ("ALSA: hda - Disable audio component for legacy Nvidia HDMI codecs") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200728082033.23933-1-tiwai@suse.de Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- sound/pci/hda/patch_hdmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/sound/pci/hda/patch_hdmi.c +++ b/sound/pci/hda/patch_hdmi.c @@ -2483,6 +2483,7 @@ static void generic_acomp_notifier_set(s mutex_lock(&spec->bind_lock); spec->use_acomp_notifier = use_acomp; spec->codec->relaxed_resume = use_acomp; + spec->codec->bus->keep_power = 0; /* reprogram each jack detection logic depending on the notifier */ if (spec->use_jack_detect) { for (i = 0; i < spec->num_pins; i++) @@ -2578,7 +2579,6 @@ static void generic_acomp_init(struct hd if (!snd_hdac_acomp_init(&codec->bus->core, &spec->drm_audio_ops, match_bound_vga, 0)) { spec->acomp_registered = true; - codec->bus->keep_power = 0; } }