On Tue, Dec 05, 2023 at 08:03:08PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> On ADL+ the hardware automagically calculates the CCS AUX surface
> stride from the main surface stride, so when remapping we can't
> really play a lot of tricks with the main surface stride, or else
> the AUX surface stride would get miscalculated and no longer
> match the actual data layout in memory.
>
> Supposedly we could remap in 256 main surface tile units
> (AUX page(4096)/cachline(64)*4(4x1 main surface tiles per
> AUX cacheline)=256 main surface tiles), but the extra complexity
> is probably not worth the hassle.
>
> So let's just make sure our mapping stride is calculated from
> the full framebuffer stride (instead of the framebuffer width).
> This way the stride we program into PLANE_STRIDE will be the
> original framebuffer stride, and thus there will be no change
> to the AUX stride/layout.
>
> Cc: Imre Deak <imre.deak@xxxxxxxxx>
> Cc: Juha-Pekka Heikkila <juhapekka.heikkila@xxxxxxxxx>
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_fb.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
> index ab634a4c86d1..9f35bdce3eb8 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb.c
> +++ b/drivers/gpu/drm/i915/display/intel_fb.c
> @@ -1509,8 +1509,20 @@ static u32 calc_plane_remap_info(const struct intel_framebuffer *fb, int color_p
>
> size += remap_info->size;
> } else {
> - unsigned int dst_stride = plane_view_dst_stride_tiles(fb, color_plane,
> - remap_info->width);
> + unsigned int dst_stride;
> +
> + /*
> + * The hardware automagically calculates the CCS AUX surface
> + * stride from the main surface stride so can't really remap a
> + * smaller subset (unless we'd remap in whole AUX page units).
> + */
> + if (intel_fb_needs_pot_stride_remap(fb) &&
This fix also applies at least to all !FLAT_CSS platforms. Since
the stride remapping is disabled anyway on all platforms for CCS
modifiers, the same should be done here as well?
> + intel_fb_is_ccs_modifier(fb->base.modifier))
> + dst_stride = remap_info->src_stride;
> + else
> + dst_stride = remap_info->width;
> +
> + dst_stride = plane_view_dst_stride_tiles(fb, color_plane, dst_stride);
>
> assign_chk_ovf(i915, remap_info->dst_stride, dst_stride);
> color_plane_info->mapping_stride = dst_stride *
> --
> 2.41.0
>
