[PATCH 3.16.y-ckt 072/104] drm/radeon: Restore LCD backlight level on resume (>= R5xx)

[Luis Henriques]

3.16.7-ckt19 -stable review patch.  If anyone has any objections, please let me know.

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

From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel.daenzer at amd.com>

commit 4281f46ef839050d2ef60348f661eb463c21cc2e upstream.

Instead of only enabling the backlight (which seems to set it to max
brightness), just re-set the current backlight level, which also takes
care of enabling the backlight if necessary.

Only the radeon_atom_encoder_dpms_dig part tested on a Kaveri laptop,
the radeon_atom_encoder_dpms_avivo part is only compile tested.

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/radeon/atombios_encoders.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index 7d68203a3737..f35008cf0bc3 100644
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -1609,8 +1609,9 @@ radeon_atom_encoder_dpms_avivo(struct drm_encoder *encoder, int mode)
 		} else
 			atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
 		if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT)) {
-			args.ucAction = ATOM_LCD_BLON;
-			atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
+			struct radeon_encoder_atom_dig *dig = radeon_encoder->enc_priv;
+
+			atombios_set_backlight_level(radeon_encoder, dig->backlight_level);
 		}
 		break;
 	case DRM_MODE_DPMS_STANDBY:
@@ -1691,8 +1692,7 @@ radeon_atom_encoder_dpms_dig(struct drm_encoder *encoder, int mode)
 				atombios_dig_encoder_setup(encoder, ATOM_ENCODER_CMD_DP_VIDEO_ON, 0);
 		}
 		if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT))
-			atombios_dig_transmitter_setup(encoder,
-						       ATOM_TRANSMITTER_ACTION_LCD_BLON, 0, 0);
+			atombios_set_backlight_level(radeon_encoder, dig->backlight_level);
 		if (ext_encoder)
 			atombios_external_encoder_setup(encoder, ext_encoder, ATOM_ENABLE);
 		break;