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

[Alex Deucher]

On Mon, Nov 4, 2024 at 4:05 AM Lu Yao <yaolu at kylinos.cn> wrote:
>
> 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?

It could, but I didn't want to imply that this should be used for all
IPs because the tiling controls are different on newer GPUs.

> >
> > +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.

It was added in patch 1.

Alex