This is a note to let you know that I've just added the patch titled drm/i915/cdclk: Fix voltage_level programming edge case to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-i915-cdclk-fix-voltage_level-programming-edge-ca.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c964396cda73ba328464682bd4511b1ce408630d Author: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Date: Tue Apr 2 18:50:04 2024 +0300 drm/i915/cdclk: Fix voltage_level programming edge case [ Upstream commit 6154cc9177ccea00c89ce0bf93352e474b819ff2 ] Currently we only consider the relationship of the old and new CDCLK frequencies when determining whether to do the repgramming from intel_set_cdclk_pre_plane_update() or intel_set_cdclk_post_plane_update(). It is technically possible to have a situation where the CDCLK frequency is decreasing, but the voltage_level is increasing due a DDI port. In this case we should bump the voltage level already in intel_set_cdclk_pre_plane_update() (so that the voltage_level will have been increased by the time the port gets enabled), while leaving the CDCLK frequency unchanged (as active planes/etc. may still depend on it). We can then reduce the CDCLK frequency to its final value from intel_set_cdclk_post_plane_update(). In order to handle that correctly we shall construct a suitable amalgam of the old and new cdclk states in intel_set_cdclk_pre_plane_update(). And we can simply call intel_set_cdclk() unconditionally in both places as it will not do anything if nothing actually changes vs. the current hw state. v2: Handle cdclk_state->disable_pipes v3: Only synchronize the cd2x update against the pipe's vblank when the cdclk frequency is changing during the current commit phase (Gustavo) Cc: stable@xxxxxxxxxxxxxxx Cc: Gustavo Sousa <gustavo.sousa@xxxxxxxxx> Reviewed-by: Uma Shankar <uma.shankar@xxxxxxxxx> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20240402155016.13733-3-ville.syrjala@xxxxxxxxxxxxxxx (cherry picked from commit 34d127e2bdef73a923aa0dcd95cbc3257ad5af52) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c index 5aa6b998a1cb1..fc3a6eb1de741 100644 --- a/drivers/gpu/drm/i915/display/intel_cdclk.c +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c @@ -2453,7 +2453,8 @@ intel_set_cdclk_pre_plane_update(struct intel_atomic_state *state) intel_atomic_get_old_cdclk_state(state); const struct intel_cdclk_state *new_cdclk_state = intel_atomic_get_new_cdclk_state(state); - enum pipe pipe = new_cdclk_state->pipe; + struct intel_cdclk_config cdclk_config; + enum pipe pipe; if (!intel_cdclk_changed(&old_cdclk_state->actual, &new_cdclk_state->actual)) @@ -2462,12 +2463,25 @@ intel_set_cdclk_pre_plane_update(struct intel_atomic_state *state) if (IS_DG2(i915)) intel_cdclk_pcode_pre_notify(state); - if (new_cdclk_state->disable_pipes || - old_cdclk_state->actual.cdclk <= new_cdclk_state->actual.cdclk) { - drm_WARN_ON(&i915->drm, !new_cdclk_state->base.changed); + if (new_cdclk_state->disable_pipes) { + cdclk_config = new_cdclk_state->actual; + pipe = INVALID_PIPE; + } else { + if (new_cdclk_state->actual.cdclk >= old_cdclk_state->actual.cdclk) { + cdclk_config = new_cdclk_state->actual; + pipe = new_cdclk_state->pipe; + } else { + cdclk_config = old_cdclk_state->actual; + pipe = INVALID_PIPE; + } - intel_set_cdclk(i915, &new_cdclk_state->actual, pipe); + cdclk_config.voltage_level = max(new_cdclk_state->actual.voltage_level, + old_cdclk_state->actual.voltage_level); } + + drm_WARN_ON(&i915->drm, !new_cdclk_state->base.changed); + + intel_set_cdclk(i915, &cdclk_config, pipe); } /** @@ -2485,7 +2499,7 @@ intel_set_cdclk_post_plane_update(struct intel_atomic_state *state) intel_atomic_get_old_cdclk_state(state); const struct intel_cdclk_state *new_cdclk_state = intel_atomic_get_new_cdclk_state(state); - enum pipe pipe = new_cdclk_state->pipe; + enum pipe pipe; if (!intel_cdclk_changed(&old_cdclk_state->actual, &new_cdclk_state->actual)) @@ -2495,11 +2509,14 @@ intel_set_cdclk_post_plane_update(struct intel_atomic_state *state) intel_cdclk_pcode_post_notify(state); if (!new_cdclk_state->disable_pipes && - old_cdclk_state->actual.cdclk > new_cdclk_state->actual.cdclk) { - drm_WARN_ON(&i915->drm, !new_cdclk_state->base.changed); + new_cdclk_state->actual.cdclk < old_cdclk_state->actual.cdclk) + pipe = new_cdclk_state->pipe; + else + pipe = INVALID_PIPE; - intel_set_cdclk(i915, &new_cdclk_state->actual, pipe); - } + drm_WARN_ON(&i915->drm, !new_cdclk_state->base.changed); + + intel_set_cdclk(i915, &new_cdclk_state->actual, pipe); } static int intel_pixel_rate_to_cdclk(const struct intel_crtc_state *crtc_state)