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 <jianshui.yu@xxxxxxxxx>
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Nirmoy Das <nirmoy.das@xxxxxxxxx>
---
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 5031ee5695dd..1aa42862a2c4 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;
}
@@ -154,8 +165,17 @@ 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);
+
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
