On Tue, Oct 04, 2022 at 11:33:10AM +0100, Matthew Auld wrote:
> For these types of display buffers, we need to able to CPU access some
> part of the backing memory in prepare_plane_clear_colors(). As a result
> we need to ensure we always place in the mappable part of lmem, which
> becomes necessary on small-bar systems.
>
> v2(Nirmoy & Ville):
> - Add some commentary for why we need to CPU access the buffer.
> - Split out the other changes, so we just consider the display change
> here.
> v3:
> - Handle this in the dpt path.
>
> Fixes: eb1c535f0d69 ("drm/i915: turn on small BAR support")
> Reported-by: Jianshui Yu <[email protected]>
> Signed-off-by: Matthew Auld <[email protected]>
> Cc: Ville Syrjälä <[email protected]>
> Cc: Nirmoy Das <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_fb_pin.c | 24 +++++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> index 32206bd359da..8197343300ee 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> @@ -50,7 +50,18 @@ intel_pin_fb_obj_dpt(struct drm_framebuffer *fb,
> continue;
>
> if (HAS_LMEM(dev_priv)) {
> - ret = i915_gem_object_migrate(obj, &ww,
> INTEL_REGION_LMEM_0);
> + unsigned int flags = obj->flags;
> +
> + /*
> + * For this type of buffer we need to able to read from
> the CPU
> + * the clear color value found in the buffer, hence we
> need to
> + * ensure it is always in the mappable part of lmem, if
> this is
> + * a small-bar device.
> + */
> + if (intel_fb_rc_ccs_cc_plane(fb) >= 0)
> + flags &= ~I915_BO_ALLOC_GPU_ONLY;
> + ret = __i915_gem_object_migrate(obj, &ww,
> INTEL_REGION_LMEM_0,
> + flags);
> if (ret)
> continue;
> }
> @@ -156,8 +167,17 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
> ret = i915_gem_object_lock(obj, &ww);
> if (!ret && phys_cursor)
> ret = i915_gem_object_attach_phys(obj, alignment);
> - else if (!ret && HAS_LMEM(dev_priv))
> + else if (!ret && HAS_LMEM(dev_priv)) {
> + /*
> + * For this type of ccs buffer we need to able to read from the
> + * CPU the clear color value found in the buffer, which might
> + * require moving to the mappable part of lmem first, but here
> + * we should be using dpt for this.
> + */
> + WARN_ON_ONCE(intel_fb_rc_ccs_cc_plane(fb) >= 0);
DPT isn't availalable on DG1.
> +
> ret = i915_gem_object_migrate(obj, &ww, INTEL_REGION_LMEM_0);
> + }
> if (!ret)
> ret = i915_gem_object_pin_pages(obj);
> if (ret)
> --
> 2.37.3
--
Ville Syrjälä
Intel
