[PATCH] drm/radeon/kms: fix s/r issues with bios scratch regs

[Alex Deucher]

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 at gmail.com>
Cc: stable at kernel.org
---
 drivers/gpu/drm/radeon/radeon_atombios.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 4dc9c51..b64e603 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);
-- 
1.7.1.1