From bcc65fd8e929a9d9d34d814d6efc1d2793546922 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <mjg@redhat.com>
Date: Mon, 8 Aug 2011 16:21:16 +0000
Subject: drm/radeon: re-POST the asic on Apple hardware when booted via EFI
Git-commit: bcc65fd8e929a9d9d34d814d6efc1d2793546922
Patch-mainline: v3.1-rc3

At least some Apples program the GPU into a state that wedges the engine
once userspace starts trying to perform accelerated operations. Executing
the Atom init scripts gets the hardware back into a working state. The
same hardware works fine when booted via BIOS emulation, so let's just
execute the init scripts on Apples when we're using EFI.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Acked-by: Michal Srb <msrb@suse.com>
---

 drivers/gpu/drm/radeon/radeon_device.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -32,6 +32,7 @@
 #include <drm/radeon_drm.h>
 #include <linux/vgaarb.h>
 #include <linux/vga_switcheroo.h>
+#include <linux/efi.h>
 #include "radeon_reg.h"
 #include "radeon.h"
 #include "atom.h"
@@ -351,6 +352,9 @@ bool radeon_card_posted(struct radeon_de
 {
 	uint32_t reg;
 
+	if (efi_enabled && rdev->pdev->subsystem_vendor == PCI_VENDOR_ID_APPLE)
+		return false;
+
 	/* first check CRTCs */
 	if (ASIC_IS_DCE4(rdev)) {
 		reg = RREG32(EVERGREEN_CRTC_CONTROL + EVERGREEN_CRTC0_REGISTER_OFFSET) |
