From 14d2000182ed1cb6baf0fe8dc60a3664a832fc01 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Mon, 11 Jan 2016 20:09:20 +0100 Subject: [PATCH] drm/radeon: Defer probe if gmux is present but its driver isn't gmux is a microcontroller built into dual GPU MacBook Pros. On pre-retina MBPs, if we're the inactive GPU, we need apple-gmux to temporarily switch DDC so that we can probe the panel's EDID. The checks for CONFIG_VGA_ARB and CONFIG_VGA_SWITCHEROO are necessary because if either of them is disabled but gmux is present, the driver would never load, even if we're the active GPU. (vga_default_device() would evaluate to NULL and vga_switcheroo_handler_flags() would evaluate to 0.) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115 Signed-off-by: Lukas Wunner Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/552da6d85a82092146af7b0693595fa2a9ea376b.1452525860.git.lukas@wunner.de --- drivers/gpu/drm/radeon/radeon_drv.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c index e266ffc520d2..cad25557650f 100644 --- a/drivers/gpu/drm/radeon/radeon_drv.c +++ b/drivers/gpu/drm/radeon/radeon_drv.c @@ -34,9 +34,11 @@ #include "radeon_drv.h" #include +#include #include #include #include +#include #include #include @@ -319,6 +321,15 @@ static int radeon_pci_probe(struct pci_dev *pdev, { int ret; + /* + * apple-gmux is needed on dual GPU MacBook Pro + * to probe the panel if we're the inactive GPU. + */ + if (IS_ENABLED(CONFIG_VGA_ARB) && IS_ENABLED(CONFIG_VGA_SWITCHEROO) && + apple_gmux_present() && pdev != vga_default_device() && + !vga_switcheroo_handler_flags()) + return -EPROBE_DEFER; + /* Get rid of things like offb */ ret = radeon_kick_out_firmware_fb(pdev); if (ret) -- 2.20.1