[PATCH] radeon: insert 10ms sleep in dce5_crtc_load_lut

[Alex Deucher]

On Tue, Jan 28, 2020 at 11:10 AM Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
>
> Per at least one tester this is enough magic to recover the regression
> introduced for some people (but not all) in
>
> commit b8e2b0199cc377617dc238f5106352c06dcd3fa2
> Author: Peter Rosin <peda at axentia.se>
> Date:   Tue Jul 4 12:36:57 2017 +0200
>
>     drm/fb-helper: factor out pseudo-palette
>
> which for radeon had the side-effect of refactoring out a seemingly
> redudant writing of the color palette.
>
> 10ms in a fairly slow modeset path feels like an acceptable form of
> duct-tape, so maybe worth a shot and see what sticks.
>
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Cc: Michel Dänzer <michel.daenzer at amd.com>
> References: https://bugzilla.kernel.org/show_bug.cgi?id=198123
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

Works for me.  Applied.  Thanks!

Alex


> ---
>  drivers/gpu/drm/radeon/radeon_display.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
> index 354756e00fe1..d07c7db0c815 100644
> --- a/drivers/gpu/drm/radeon/radeon_display.c
> +++ b/drivers/gpu/drm/radeon/radeon_display.c
> @@ -127,6 +127,8 @@ static void dce5_crtc_load_lut(struct drm_crtc *crtc)
>
>         DRM_DEBUG_KMS("%d\n", radeon_crtc->crtc_id);
>
> +       msleep(10);
> +
>         WREG32(NI_INPUT_CSC_CONTROL + radeon_crtc->crtc_offset,
>                (NI_INPUT_CSC_GRPH_MODE(NI_INPUT_CSC_BYPASS) |
>                 NI_INPUT_CSC_OVL_MODE(NI_INPUT_CSC_BYPASS)));
> --
> 2.24.1
>
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