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
Thanks,
Lukas
Lukas Wunner (12): vga_switcheroo: Add handler flags infrastructure vga_switcheroo: Add support for switching only the DDC apple-gmux: Track switch state apple-gmux: Add switch_ddc support drm/edid: Switch DDC when reading the EDID drm/i915: Switch DDC when reading the EDID drm/nouveau: Switch DDC when reading the EDID drm/radeon: Switch DDC when reading the EDID apple-gmux: Add helper for presence detect drm/i915: Defer probe if gmux is present but its driver isn't drm/nouveau: Defer probe if gmux is present but its driver isn't drm/radeon: Defer probe if gmux is present but its driver isn't
Documentation/DocBook/gpu.tmpl | 5 + drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c | 3 +- drivers/gpu/drm/drm_edid.c | 26 +++++ drivers/gpu/drm/i915/i915_drv.c | 12 +++ drivers/gpu/drm/i915/intel_lvds.c | 8 +- drivers/gpu/drm/nouveau/nouveau_acpi.c | 2 +- drivers/gpu/drm/nouveau/nouveau_connector.c | 21 +++- drivers/gpu/drm/nouveau/nouveau_drm.c | 11 +++ drivers/gpu/drm/radeon/radeon_atpx_handler.c | 3 +- drivers/gpu/drm/radeon/radeon_connectors.c | 6 ++ drivers/gpu/drm/radeon/radeon_drv.c | 11 +++ drivers/gpu/vga/vga_switcheroo.c | 119 ++++++++++++++++++++++- drivers/platform/x86/apple-gmux.c | 111 ++++++++++++++++----- include/drm/drm_crtc.h | 2 + include/linux/apple-gmux.h | 39 ++++++++ include/linux/vga_switcheroo.h | 36 ++++++- 16 files changed, 382 insertions(+), 33 deletions(-) create mode 100644 include/linux/apple-gmux.h