Re: [PATCH 1/2] Revert "drm/amd: Remove freesync video mode amdgpu parameter"

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 27.02.24 um 19:48 schrieb Alex Deucher:
> This reverts commit e94e787e37b99645e7c02d20d0a1ba0f8a18a82a.
>
> This conflicts with how compositors want to handle VRR.  Now
> that compositors actually handle VRR, we probably don't need
> freesync video.
>
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2985

Scratching my head what actually happens here? Doesn't the problem then 
just depend on a module parameter?

Regards,
Christian.

> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu.h     |  1 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 27 +++++++++++++++++++++++++
>   2 files changed, 28 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 0e365cadcc3fc..925026c183f41 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -194,6 +194,7 @@ extern int amdgpu_emu_mode;
>   extern uint amdgpu_smu_memory_pool_size;
>   extern int amdgpu_smu_pptable_id;
>   extern uint amdgpu_dc_feature_mask;
> +extern uint amdgpu_freesync_vid_mode;
>   extern uint amdgpu_dc_debug_mask;
>   extern uint amdgpu_dc_visual_confirm;
>   extern int amdgpu_dm_abm_level;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index 15a8a64fc4e28..82b154b103f43 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -199,6 +199,7 @@ int amdgpu_mes_kiq;
>   int amdgpu_noretry = -1;
>   int amdgpu_force_asic_type = -1;
>   int amdgpu_tmz = -1; /* auto */
> +uint amdgpu_freesync_vid_mode;
>   int amdgpu_reset_method = -1; /* auto */
>   int amdgpu_num_kcq = -1;
>   int amdgpu_smartshift_bias;
> @@ -883,6 +884,32 @@ module_param_named(damageclips, amdgpu_damage_clips, int, 0444);
>   MODULE_PARM_DESC(tmz, "Enable TMZ feature (-1 = auto (default), 0 = off, 1 = on)");
>   module_param_named(tmz, amdgpu_tmz, int, 0444);
>   
> +/**
> + * DOC: freesync_video (uint)
> + * Enable the optimization to adjust front porch timing to achieve seamless
> + * mode change experience when setting a freesync supported mode for which full
> + * modeset is not needed.
> + *
> + * The Display Core will add a set of modes derived from the base FreeSync
> + * video mode into the corresponding connector's mode list based on commonly
> + * used refresh rates and VRR range of the connected display, when users enable
> + * this feature. From the userspace perspective, they can see a seamless mode
> + * change experience when the change between different refresh rates under the
> + * same resolution. Additionally, userspace applications such as Video playback
> + * can read this modeset list and change the refresh rate based on the video
> + * frame rate. Finally, the userspace can also derive an appropriate mode for a
> + * particular refresh rate based on the FreeSync Mode and add it to the
> + * connector's mode list.
> + *
> + * Note: This is an experimental feature.
> + *
> + * The default value: 0 (off).
> + */
> +MODULE_PARM_DESC(
> +	freesync_video,
> +	"Enable freesync modesetting optimization feature (0 = off (default), 1 = on)");
> +module_param_named(freesync_video, amdgpu_freesync_vid_mode, uint, 0444);
> +
>   /**
>    * DOC: reset_method (int)
>    * GPU reset method (-1 = auto (default), 0 = legacy, 1 = mode0, 2 = mode1, 3 = mode2, 4 = baco)