On 05.09.2022 13:48, Ville Syrjälä wrote:
On Mon, Sep 05, 2022 at 10:05:00AM +0200, Andrzej Hajda wrote:In case of ICL and older generations disabling plane and/or disabling async update is always performed on vblank,It should only be broken on bdw-glk (see. need_async_flip_disable_wa).
On CFL it is reported every drmtip run: https://intel-gfx-ci.01.org/tree/drm-tip/drmtip.html?testfilter=tiled-max-hw https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_1209/fi-cfl-8109u/igt@kms_big_fb@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx#dmesg-warnings402 https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_1209/fi-cfl-8109u/igt@kms_big_fb@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx#dmesg-warnings402 https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_1209/fi-cfl-8109u/igt@kms_big_fb@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_1208/fi-cfl-8109u/igt@kms_big_fb@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ...On APL it is less frequent, probably due to other bugs preventing run of this test, last seen at:
https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_1190/fi-apl-guc/igt@kms_big_fb@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Similar for SKL: https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_1181/fi-skl-guc/igt@kms_big_fb@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxI am not sure if I correctly read the docs but [1] says that 9th bit of PLANE_CFG (Async Address Update Enable) is "not double buffered and the changes will apply immediately" only for ICL, JSL, LKF1.
So the change is not necessary in case of icl_plane_disable_arm. [1]: https://gfxspecs.intel.com/Predator/Home/Index/7656
but if async update is enabled PLANE_SURF register is updated asynchronously. Writing 0 to PLANE_SURF when plane is still enabled can cause DMAR/PIPE errors. On the other side PLANE_SURF is used to arm plane registers - we need to write to it to trigger update on VBLANK, writting current value should be safe - the buffer address is valid till vblank.I think you're effectively saying that somehow the async flip disable w/a is not kicking in sometimes.
I was not aware of existence of this w/a and I am little lost in figuring out how this w/a can prevent zeroing PLANE_SURF too early.
Regards Andrzej
Signed-off-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx> --- drivers/gpu/drm/i915/display/skl_universal_plane.c | 8 ++++++-- 1 file changed, 6 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 bcfde81e4d0866..bc9ed60a2d349e 100644 --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c @@ -615,11 +615,13 @@ skl_plane_disable_arm(struct intel_plane *plane, struct drm_i915_private *dev_priv = to_i915(plane->base.dev); enum plane_id plane_id = plane->id; enum pipe pipe = plane->pipe; + u32 plane_surf;skl_write_plane_wm(plane, crtc_state); intel_de_write_fw(dev_priv, PLANE_CTL(pipe, plane_id), 0);- intel_de_write_fw(dev_priv, PLANE_SURF(pipe, plane_id), 0); + plane_surf = intel_de_read_fw(dev_priv, PLANE_SURF(pipe, plane_id)); + intel_de_write_fw(dev_priv, PLANE_SURF(pipe, plane_id), plane_surf); }static void@@ -629,6 +631,7 @@ icl_plane_disable_arm(struct intel_plane *plane, struct drm_i915_private *dev_priv = to_i915(plane->base.dev); enum plane_id plane_id = plane->id; enum pipe pipe = plane->pipe; + u32 plane_surf;if (icl_is_hdr_plane(dev_priv, plane_id))intel_de_write_fw(dev_priv, PLANE_CUS_CTL(pipe, plane_id), 0); @@ -637,7 +640,8 @@ icl_plane_disable_arm(struct intel_plane *plane,intel_psr2_disable_plane_sel_fetch(plane, crtc_state);intel_de_write_fw(dev_priv, PLANE_CTL(pipe, plane_id), 0); - intel_de_write_fw(dev_priv, PLANE_SURF(pipe, plane_id), 0); + plane_surf = intel_de_read_fw(dev_priv, PLANE_SURF(pipe, plane_id)); + intel_de_write_fw(dev_priv, PLANE_SURF(pipe, plane_id), plane_surf); }static bool-- 2.25.1
