[PATCH] drm/amd/display: Look at firmware version to determine using dmub on dcn21

[Alex Deucher]

On Fri, Oct 29, 2021 at 4:12 PM Mario Limonciello
<mario.limonciello at amd.com> wrote:
>
> commit b1c61212d8dc ("drm/amd/display: Fully switch to dmub for all dcn21
> asics") switched over to using dmub on Renoir to fix Gitlab 1735, but this
> implied a new dependency on newer firmware which might not be met on older
> kernel versions.
>
> Since sw_init runs before hw_init, there is an opportunity to determine
> whether or not the firmware version is new to adjust the behavior.
>
> Cc: Roman.Li at amd.com
> BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1772
> BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1735
> Fixes: b1c61212d8dc ("drm/amd/display: Fully switch to dmub for all dcn21 asics")
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>

Acked-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +-
>  1 file changed, 1 insertion(+), 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 6dd6262f2769..85b3de97f870 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1410,7 +1410,7 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
>                 switch (adev->ip_versions[DCE_HWIP][0]) {
>                 case IP_VERSION(2, 1, 0):
>                         init_data.flags.gpu_vm_support = true;
> -                       init_data.flags.disable_dmcu = true;
> +                       init_data.flags.disable_dmcu = adev->dm.dmcub_fw_version > 0x01000000;
>                         break;
>                 case IP_VERSION(1, 0, 0):
>                 case IP_VERSION(1, 0, 1):
> --
> 2.25.1
>