[PATCH 0/2] Audio client support for VGA-switcheroo

[Takashi Iwai]

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?


thanks,

Takashi