[PATCH v5 00/12] Enable GPU switching on pre-retina MacBook Pro

[Daniel Vetter]

On Mon, Feb 08, 2016 at 10:10:00AM -0800, Darren Hart wrote:
> On Mon, Jan 11, 2016 at 08:09:20PM +0100, Lukas Wunner wrote:
> > Enable GPU switching on the pre-retina MacBook Pro (2008 - 2013), v5.
> > 
> > The main obstacle on these machines is that the panel mode in VBIOS
> > is bogus. Fortunately gmux can switch DDC independently from the
> > display, thereby allowing the inactive GPU to probe the panel's EDID.
> > 
> > In short, vga_switcheroo and apple-gmux are amended with hooks to
> > switch DDC, DRM core is amended with a drm_get_edid_switcheroo() helper,
> > and relevant drivers are amended to call that for LVDS outputs.
> > 
> > The retina MacBook Pro (2012 - present) uses eDP and cannot switch
> > AUX independently from the main link. The main obstacle there is link
> > training, I'm currently working on this, it will be addressed in a
> > future patch set.
> > 
> > This series is also reviewable on GitHub:
> > https://github.com/l1k/linux/commits/mbp_switcheroo_v5
> > 
> > Changes:
> > 
> > * New patch [01/12]: vga_switcheroo handler flags
> >   Alex Deucher asked if this series might regress on non-Apple laptops.
> >   To address this concern, I let handlers declare their capabilities in
> >   a bitmask. DRM drivers call drm_get_edid_switcheroo() only if the
> >   handler has set the VGA_SWITCHEROO_CAN_SWITCH_DDC flag.
> >   Currently just one other flag is defined which is used on retinas.
> > 
> > * Changed patch [02/12]: vga_switcheroo DDC locking
> >   Rename ddc_lock to mux_hw_lock, suggested by Daniel Vetter.
> > 
> > * New patch [03/12]: track switch state of apple-gmux
> >   Fixes a bug in previous versions of this series which occurred if
> >   the system was suspended while DDC was temporarily switched:
> >   On resume DDC was switched to the wrong GPU.
> > 
> > * New patches [09/12 - 12/12]: deferred probing
> >   Previously I used connector reprobing if the inactive GPU's driver
> >   loaded before gmux. I've ditched that in favor of deferred driver
> >   probing, which is much simpler. Thanks to Daniel Vetter for the
> >   suggestion.
> > 
> > Caution: Patch [09/12] depends on a new acpi_dev_present() API which
> > will land in 4.5 via Rafael J. Wysocki's tree.
> > 
> > I would particularly be interested in feedback on the handler flags
> > patch [01/12]. I'm not 100% happy with the number of characters
> > required to query the flags (e.g.: if (vga_switcheroo_handler_flags() &
> > VGA_SWITCHEROO_CAN_SWITCH_DDC)), but failed to come up with something
> > shorter. Thierry Reding used a struct of bools instead of a bitmask
> > for his recent drm_dp_link_caps patches. Maybe use that instead?
> > http://lists.freedesktop.org/archives/dri-devel/2015-December/097025.html
> 
> No objection from the platform-driver-x86 side. I can pull these separately once
> the core is in, or these can be included with that core (preferred) with my
> Reviewed-by for 1, 3, 4, and 9.
> 
> Reviewed-by: Darren Hart <dvhart at linux.intel.com>

I pulled them all in through drm-misc, thanks.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch