At Thu, 10 May 2012 09:08:38 +0200, Takashi Iwai wrote:
Dave,
this is a small patch series to add the support for audio clients to VGA switcheroo. The background problem is that the HD-audio HDMI controller of the discrete GPU is also disabled when the graphics core is disabled by vga-switcheroo. This leads to a long stall of the audio driver, or at worst, it Oopses. https://bugzilla.kernel.org/show_bug.cgi?id=43155
I tried to work around it only in the audio driver side, but it doesn't seem to help. When the graphics is disabled, the whole PCI entry can't be accessed any longer. Even reading a config triggers an Oops. So, the only option is to implement the VGA switcheroo client for the audio.
The first patch refactors the vga-switcheroo code to be ready to accept for more than two clients. It's mostly a clean up using linked lists. The next patch implements the audio client registration.
BTW, if these patches are OK, the question remains how to merge. Obviously I'd need more patches for HD-audio driver based on the new vga_switcheroo_register_audio_client(). One option is to apply these patches to a persistent branch (i.e. no rebase planned) of your tree and pull it to my tree with more patches for HD-audio. Does it sound good for you?
Or, if you prefer, just pull from topic/vga-switcheroo branch of my tree: git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git topic/vga-switcheroo
Takashi