[PATCH] drm/radeon: enable native backlight control on old macs

[Alex Deucher]

Commit b7bc596ebbe0cddc97d76ef9309f64471bbf13eb accidently
broke backlight control on old mac laptops that use the
on-GPU backlight controller.

Reported by nathanhi on IRC.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/radeon/radeon_encoders.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_encoders.c b/drivers/gpu/drm/radeon/radeon_encoders.c
index 6b670b0..275ed45 100644
--- a/drivers/gpu/drm/radeon/radeon_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_encoders.c
@@ -179,6 +179,9 @@ static void radeon_encoder_add_backlight(struct radeon_encoder *radeon_encoder,
 		    (rdev->pdev->subsystem_vendor == 0x1734) &&
 		    (rdev->pdev->subsystem_device == 0x1107))
 			use_bl = false;
+		/* enable native backlight control on apple */
+		else if (rdev->pdev->subsystem_vendor == PCI_VENDOR_ID_APPLE)
+			use_bl = true;
 		/* disable native backlight control on older asics */
 		else if (rdev->family < CHIP_R600)
 			use_bl = false;
-- 
1.8.3.1