tree 67e4e96bc3729d14b2dd72d704149be3eb141a95
parent e87a52b38943608531ff63ea397b1ae5dd48e341
author Lukas Wunner <lukas@wunner.de> 1452539360 +0100
committer Daniel Vetter <daniel.vetter@ffwll.ch> 1455013267 +0100

vga_switcheroo: Add handler flags infrastructure

Allow handlers to declare their capabilities and allow clients to
obtain that information. So far we have these use cases:

* If the handler is able to switch DDC separately, clients need to
  probe EDID with drm_get_edid_switcheroo(). We should allow them
  to detect a capable handler to ensure this function only gets
  called when needed.

* Likewise if the handler is unable to switch AUX separately, the active
  client needs to communicate link training parameters to the inactive
  client, which may then skip the AUX handshake and set up its output
  with these pre-calibrated values (DisplayPort specification v1.1a,
  section 2.5.3.3). Clients need a way to recognize such a situation.

The flags for the radeon_atpx_handler and amdgpu_atpx_handler are
initially set to 0, this can later on be amended with
  handler_flags |= VGA_SWITCHEROO_CAN_SWITCH_DDC;
when a ->switch_ddc callback is added.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115
Tested-by: Lukas Wunner <lukas@wunner.de>
    [MBP  9,1 2012  intel IVB + nvidia GK107  pre-retina  15"]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/2b0d93ed6e511ca09e95e45e0b35627f330fabce.1452525860.git.lukas@wunner.de