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Commit 98b3a340 authored by Lukas Wunner's avatar Lukas Wunner Committed by Daniel Vetter
Browse files

drm/nouveau: 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://bugzilla.kernel.org/show_bug.cgi?id=88861
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115


Tested-by: default avatarLukas Wunner <lukas@wunner.de>
    [MBP  9,1 2012  intel IVB + nvidia GK107  pre-retina  15"]
Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/d9542ca5041178165d3ff286c90cc99634f7d2ce.1452525860.git.lukas@wunner.de
parent 704ab614

drivers/gpu/drm/nouveau/nouveau_drm.c

+11 −0
Original line number Diff line number Diff line
@@ -22,11 +22,13 @@ 
 * Authors: Ben Skeggs

 */



#include <linux/apple-gmux.h>

#include <linux/console.h>

#include <linux/delay.h>

#include <linux/module.h>

#include <linux/pci.h>

#include <linux/pm_runtime.h>

#include <linux/vgaarb.h>

#include <linux/vga_switcheroo.h>



#include "drmP.h"
@@ -312,6 +314,15 @@ static int nouveau_drm_probe(struct pci_dev *pdev, 
	bool boot = false;

	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;



	/* remove conflicting drivers (vesafb, efifb etc) */

	aper = alloc_apertures(3);

	if (!aper)