Hello,
Den 2024-10-03 kl. 18:14, skrev Ville Syrjälä:
On Thu, Oct 03, 2024 at 05:44:12PM +0200, Maarten Lankhorst wrote:
I'm planning to reorder readout in the Xe sequence in such a way that
interrupts will not be available, so just use an async flip.
Since the new FB points to the same pages, it will not tear. It also
has the benefit of perhaps being slightly faster.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/skl_universal_plane.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
index fdb141cfa4274..73a3624e34098 100644
--- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
+++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
@@ -2800,7 +2800,7 @@ bool skl_fixup_initial_plane_config(struct intel_crtc *crtc,
to_intel_plane_state(plane->base.state);
enum plane_id plane_id = plane->id;
enum pipe pipe = crtc->pipe;
- u32 base;
+ u32 base, plane_ctl;
if (!plane_state->uapi.visible)
return false;
@@ -2814,7 +2814,16 @@ bool skl_fixup_initial_plane_config(struct intel_crtc *crtc,
if (plane_config->base == base)
return false;
+ /* Perform an async flip to the new surface. */
+ plane_ctl = intel_read(i915, PLANE_CTL(pipe, plane_id));
+ plane_ctl |= PLANE_CTL_ASYNC_FLIP;
+
No async flips!
Can you please explain your reasoning? I think async flip would fit
perfectly here. We cannot perform a wait_for_vblank as we will not have
interrupts enabled yet. Additionally an async flip would cause a faster
driver loading. Since the FB is exactly the same except set to a
different address, no tearing will occur.
Cheers,
~Maarten
