drm/radeon: enable native backlight control on old macs

Commit b7bc596ebbe0 ("drm/radeon: disable native
backlight control on pre-r6xx asics (v2)") accidently
broke backlight control on old mac laptops that use the
on-GPU backlight controller.

Signed-off-by: Nathan-J. Hirschauer <nathanhi@deepserve.info>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_encoders.c b/drivers/gpu/drm/radeon/radeon_encoders.c
index 6b670b0bc47b..3a297037cc17 100644
--- a/drivers/gpu/drm/radeon/radeon_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_encoders.c
@@ -179,9 +179,12 @@ static void radeon_encoder_add_backlight(struct radeon_encoder *radeon_encoder,
                     (rdev->pdev->subsystem_vendor == 0x1734) &&
                     (rdev->pdev->subsystem_device == 0x1107))
                         use_bl = false;
+/* Older PPC macs use on-GPU backlight controller */
+#ifndef CONFIG_PPC_PMAC
                 /* disable native backlight control on older asics */
                 else if (rdev->family < CHIP_R600)
                         use_bl = false;
+#endif
                 else
                         use_bl = true;
         }