On 2021-11-30 09:53, Nicholas Kazlauskas wrote:
> [Why]
> PSR currently relies on the kernel's delayed vblank on/off mechanism
> as an implicit bufferring mechanism to prevent excessive entry/exit.
>
> Without this delay the user experience is impacted since it can take
> a few frames to enter/exit.
>
> [How]
> Only allow vblank disable immediate for DC when psr is not supported.
>
> Leave a TODO indicating that this support should be extended in the
> future to delay independent of the vblank interrupt.
>
> Fixes: 3d1508b73ff1 ("drm/amdgpu/display: set vblank_disable_immediate for DC")
>
> Cc: Harry Wentland <harry.wentland@xxxxxxx>
> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
Now I'm curious whether vblank_disable_immediate or PSR
save more power.
Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx>
Harry
> ---
> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> 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 0747dc7922c2..d582d44c02ad 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1599,9 +1599,6 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
> adev_to_drm(adev)->mode_config.cursor_width = adev->dm.dc->caps.max_cursor_size;
> adev_to_drm(adev)->mode_config.cursor_height = adev->dm.dc->caps.max_cursor_size;
>
> - /* Disable vblank IRQs aggressively for power-saving */
> - adev_to_drm(adev)->vblank_disable_immediate = true;
> -
> if (drm_vblank_init(adev_to_drm(adev), adev->dm.display_indexes_num)) {
> DRM_ERROR(
> "amdgpu: failed to initialize sw for display support.\n");
> @@ -4264,6 +4261,14 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
>
> }
>
> + /*
> + * Disable vblank IRQs aggressively for power-saving.
> + *
> + * TODO: Fix vblank control helpers to delay PSR entry to allow this when PSR
> + * is also supported.
> + */
> + adev_to_drm(adev)->vblank_disable_immediate = !psr_feature_enabled;
> +
> /* Software is initialized. Now we can register interrupt handlers. */
> switch (adev->asic_type) {
> #if defined(CONFIG_DRM_AMD_DC_SI)
>
