[PATCH 3.10 56/79] drm/radeon/DCE4+: clear bios scratch dpms bit (v2)

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alex Deucher <alexander.deucher@amd.com>

commit 6802d4bad83f50081b2788698570218aaff8d10e upstream.

The BlankCrtc table in some DCE8 boards has some
logic shortcuts for the vbios when this bit is set.
Clear it for driver use.

v2: fix typo

Bug:
https://bugs.freedesktop.org/show_bug.cgi?id=73420

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -2926,6 +2926,10 @@ void radeon_atom_initialize_bios_scratch
 	/* tell the bios not to handle mode switching */
 	bios_6_scratch |= ATOM_S6_ACC_BLOCK_DISPLAY_SWITCH;
 
+	/* clear the vbios dpms state */
+	if (ASIC_IS_DCE4(rdev))
+		bios_2_scratch &= ~ATOM_S2_DEVICE_DPMS_STATE;
+
 	if (rdev->family >= CHIP_R600) {
 		WREG32(R600_BIOS_2_SCRATCH, bios_2_scratch);
 		WREG32(R600_BIOS_6_SCRATCH, bios_6_scratch);