@@ -34,9 +34,11 @@
#include "radeon_drv.h"
#include <drm/drm_pciids.h>
+#include <linux/apple-gmux.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
+#include <linux/vgaarb.h>
#include <linux/vga_switcheroo.h>
#include <drm/drm_gem.h>
@@ -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)
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 <lukas@wunner.de> --- drivers/gpu/drm/radeon/radeon_drv.c | 11 +++++++++++ 1 file changed, 11 insertions(+)