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>

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 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);