[PATCH 4/4] drm/amd/display: add non-DC drm_panic support

[Lu Yao]

on 2024/11/1 02:04, Alex Deucher wrote:
> Add support for the drm_panic module, which displays a pretty user
> friendly message on the screen when a Linux kernel panic occurs.
>
> Adapt Lu Yao's code to use common helpers derived from
> Jocelyn's patch.  This extends the non-DC code to enable
> access to non-CPU accessible VRAM and adds support for
> other DCE versions.
>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> Cc: Lu Yao <yaolu at kylinos.cn>
> Cc: Jocelyn Falempe <jfalempe at redhat.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/dce_v10_0.c | 27 ++++++++++++++++++++++++++
>  drivers/gpu/drm/amd/amdgpu/dce_v11_0.c | 27 ++++++++++++++++++++++++++
>  drivers/gpu/drm/amd/amdgpu/dce_v6_0.c  | 27 ++++++++++++++++++++++++++
>  drivers/gpu/drm/amd/amdgpu/dce_v8_0.c  | 26 +++++++++++++++++++++++++
>  4 files changed, 107 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> index 5098c50d54c8..a26f2381504b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> @@ -2687,6 +2687,32 @@ static const struct drm_crtc_helper_funcs dce_v10_0_crtc_helper_funcs = {
>  	.get_scanout_position = amdgpu_crtc_get_scanout_position,
>  };
>  
> +static void dce_v10_0_panic_flush(struct drm_plane *plane)
> +{
> +	struct drm_framebuffer *fb;
> +	struct amdgpu_crtc *amdgpu_crtc;
> +	struct amdgpu_device *adev;
> +	uint32_t fb_format;
> +
> +	if (!plane->fb)
> +		return;
> +
> +	fb = plane->fb;
> +	amdgpu_crtc = to_amdgpu_crtc(plane->crtc);
> +	adev = drm_to_adev(fb->dev);
> +
> +	/* Disable DC tiling */
> +	fb_format = RREG32(mmGRPH_CONTROL + amdgpu_crtc->crtc_offset);
> +	fb_format &= ~GRPH_CONTROL__GRPH_ARRAY_MODE_MASK;
> +	WREG32(mmGRPH_CONTROL + amdgpu_crtc->crtc_offset, fb_format);
> +
> +}
> +
For non-DC ip, 'mmGRPH_CONTROL' and 'GRPH_CONTROL__GRPH_ARRAY_MODE_MASK' val are same, so whether the panic_flush function can also be made same?
>
> +static const struct drm_plane_helper_funcs dce_v10_0_drm_primary_plane_helper_funcs = {
> +	.get_scanout_buffer = amdgpu_display_get_scanout_buffer,
The definition of 'amdgpu_display_get_scanout_buffer' seems to be missing.