Newer DMUB firmware on Renoir and Green Sardine do not need to disable dmcu and this actually causes problems with DP-C alt mode for a number of machines.

Backport the fix from this from mainline. It's a hand modified backport because mainline switched to IP version checking which doesn't exist in linux-stable.

BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1772 BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1735 Signed-off-by: Mario Limonciello mario.limonciello@amd.com Reviewed-by: Alex Deucher alexander.deucher@amd.com --- Resend, also pick up Alex's tag from last submission This was previously sent to stable@kernel.org not stable@vger.kernel.org.

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 1ea31dcc7a8b..084491afe540 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -1141,8 +1141,15 @@ static int amdgpu_dm_init(struct amdgpu_device *adev) case CHIP_RAVEN: case CHIP_RENOIR: init_data.flags.gpu_vm_support = true; - if (ASICREV_IS_GREEN_SARDINE(adev->external_rev_id)) + switch (adev->dm.dmcub_fw_version) { + case 0: /* development */ + case 0x1: /* linux-firmware.git hash 6d9f399 */ + case 0x01000000: /* linux-firmware.git hash 9a0b0f4 */ + init_data.flags.disable_dmcu = false; + break; + default: init_data.flags.disable_dmcu = true; + } break; case CHIP_VANGOGH: case CHIP_YELLOW_CARP: