drm/i915/cdclk: Fix voltage_level programming edge case

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@vger.kernel.org
Cc: Gustavo Sousa <gustavo.sousa@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240402155016.13733-3-ville.syrjala@linux.intel.com
(cherry picked from commit 34d127e2bd)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This commit is contained in:
Ville Syrjälä 2024-04-02 18:50:04 +03:00 committed by Rodrigo Vivi
parent 7b1f6b5aae
commit 6154cc9177
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GPG Key ID: FA625F640EEB13CA

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@ -2534,7 +2534,8 @@ 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))
@ -2543,12 +2544,25 @@ 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);
}
/**
@ -2566,7 +2580,7 @@ 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))
@ -2576,11 +2590,14 @@ 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)