drm/radeon: Fix backlight control on iMac 12,1

commit 364438fd629f7611a84c8e6d7de91659300f1502 upstream.

The iMac 12,1 does not use the gmux driver for backlight, so the radeon
backlight device is needed to set the brightness.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1838
Signed-off-by: Nicholas Bishop <nicholasbishop@google.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nicholas Bishop 2022-02-11 14:57:39 -05:00 committed by Greg Kroah-Hartman
parent 494de920d9
commit 13f6ebef03

View File

@ -197,7 +197,8 @@ void radeon_atom_backlight_init(struct radeon_encoder *radeon_encoder,
* so don't register a backlight device
*/
if ((rdev->pdev->subsystem_vendor == PCI_VENDOR_ID_APPLE) &&
(rdev->pdev->device == 0x6741))
(rdev->pdev->device == 0x6741) &&
!dmi_match(DMI_PRODUCT_NAME, "iMac12,1"))
return;
if (!radeon_encoder->enc_priv)