From 87364760de5d631390c478fcbac8db1b926e0adf Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexdeucher@gmail.com>
Date: Wed, 2 Feb 2011 19:46:06 -0500
Subject: [PATCH] drm/radeon/kms: fix s/r issues with bios scratch regs

The accelerate mode bit gets checked by certain atom
command tables to set up some register state.  It needs
to be clear when setting modes and set when not.

Fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=26942

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
---
 drivers/gpu/drm/radeon/radeon_atombios.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 4dc9c518c2fe..b64e6034b45f 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -2609,7 +2609,7 @@ void radeon_atom_initialize_bios_scratch_regs(struct drm_device *dev)
 	bios_2_scratch &= ~ATOM_S2_VRI_BRIGHT_ENABLE;
 
 	/* tell the bios not to handle mode switching */
-	bios_6_scratch |= (ATOM_S6_ACC_BLOCK_DISPLAY_SWITCH | ATOM_S6_ACC_MODE);
+	bios_6_scratch |= ATOM_S6_ACC_BLOCK_DISPLAY_SWITCH;
 
 	if (rdev->family >= CHIP_R600) {
 		WREG32(R600_BIOS_2_SCRATCH, bios_2_scratch);
@@ -2660,10 +2660,13 @@ void radeon_atom_output_lock(struct drm_encoder *encoder, bool lock)
 	else
 		bios_6_scratch = RREG32(RADEON_BIOS_6_SCRATCH);
 
-	if (lock)
+	if (lock) {
 		bios_6_scratch |= ATOM_S6_CRITICAL_STATE;
-	else
+		bios_6_scratch &= ~ATOM_S6_ACC_MODE;
+	} else {
 		bios_6_scratch &= ~ATOM_S6_CRITICAL_STATE;
+		bios_6_scratch |= ATOM_S6_ACC_MODE;
+	}
 
 	if (rdev->family >= CHIP_R600)
 		WREG32(R600_BIOS_6_SCRATCH, bios_6_scratch);
-- 
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