On Wed, 12 Sep 2018 11:48:33 +0200, Takashi Iwai wrote: > > The recent change of vga_switcheroo allowed the runtime PM for > HD-audio on AMD GPU, but this also resulted in a regression. When the > HD-audio controller driver gets runtime-suspended, HD-audio link is > turned off, and the hotplug notification is ignored. This leads to > the inconsistent audio state (the connection isn't notified and ELD is > ignored). > > The best fix would be to implement the proper ELD notification via the > audio component, but it's still not ready. As a quick workaround, > this patch adds the check of runtime_idle and allows the runtime > suspend only when the vga_switcheroo is bound with discrete GPU. > That is, a system with a single GPU would be again without runtime PM > (of the controller), as well as the APU that needs to keep the > HD-audio link for the hotplug notification and ELD read out. > > For identifying the audio client connection type, a new API is added > to vga_switcheroo. Other than that, the patch does a pretty simple > job. > > Note that this patch won't influence on the HD-audio *codec* runtime > PM. When a codec is unused and the system goes to S3/S4 and resumed, > the codec won't be resumed immediately because it's unused. This > likely keeps the hotplug notification broken, but this is basically > the expected behavior, a cost needed for the power-saving. The > hotplug state will be activated once when you access to the device (or > triggering the power up via reading a codec#* proc file or such). > > Again, this issue will be solved by the proper audio component > notification, but it's still not ready. Until then, user would need > to disable the power-saving explicitly if the ELD hotplug notification > is required. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200945 > Fixes: 07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller") > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Scratch this one. It still has a problem of the forced codec->auto_runtime_pm flag. The v2 patch (with a completely different implementation) seems working better, according to Bugzilla report. Will submit v2 patch. thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
