The pre-retina MacBook Pro uses an LVDS panel and a gmux controller to switch the panel between its two GPUs. The panel mode in VBIOS is notoriously bogus on these machines and some models have no VBIOS at all.
Use drm_get_edid_switcheroo() in lieu of drm_get_edid() on LVDS if the vga_switcheroo handler is capable of temporarily switching the panel's DDC lines to the integrated GPU. This allows us to retrieve the EDID if the panel is currently muxed to the discrete GPU.
This only enables EDID probing on the pre-retina MBP (2008 - 2013). The retina MBP (2012 - present) uses eDP and gmux is not capable of switching AUX separately from the main link on these models. This will be addressed in later patches.
List of pre-retina MBPs with dual GPUs, one of them Intel: [MBP 6,2 2010 intel ILK + nvidia GT216 pre-retina 15"] [MBP 6,1 2010 intel ILK + nvidia GT216 pre-retina 17"] [MBP 8,2 2011 intel SNB + amd turks pre-retina 15"] [MBP 8,3 2011 intel SNB + amd turks pre-retina 17"] [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina 15"]
v3: Commit newly added due to introduction of drm_get_edid_switcheroo() wrapper which drivers need to opt-in to.
v5: Rebase on "vga_switcheroo: Add handler flags infrastructure", i.e. call drm_get_edid_switcheroo() only if the handler indicates that DDC is switchable.
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 --- drivers/gpu/drm/i915/intel_lvds.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index 0da0240..811ddf7 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -31,6 +31,7 @@ #include <linux/dmi.h> #include <linux/i2c.h> #include <linux/slab.h> +#include <linux/vga_switcheroo.h> #include <drm/drmP.h> #include <drm/drm_atomic_helper.h> #include <drm/drm_crtc.h> @@ -1080,7 +1081,12 @@ void intel_lvds_init(struct drm_device *dev) * preferred mode is the right one. */ mutex_lock(&dev->mode_config.mutex); - edid = drm_get_edid(connector, intel_gmbus_get_adapter(dev_priv, pin)); + if (vga_switcheroo_handler_flags() & VGA_SWITCHEROO_CAN_SWITCH_DDC) + edid = drm_get_edid_switcheroo(connector, + intel_gmbus_get_adapter(dev_priv, pin)); + else + edid = drm_get_edid(connector, + intel_gmbus_get_adapter(dev_priv, pin)); if (edid) { if (drm_add_edid_modes(connector, edid)) { drm_mode_connector_update_edid_property(connector,