> -----Original Message-----
> From: Intel-gfx <intel-gfx-boun...@lists.freedesktop.org> On Behalf Of Mika
> Kahola
> Sent: Friday, November 19, 2021 3:14 PM
> To: intel-gfx@lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH v2 5/5] drm/i915: Allow cdclk squasher to be
> reconfigured live
>
> From: Ville Syrjälä <ville.syrj...@linux.intel.com>
>
> Supposedly we should be able to change the cdclk squasher waveform even
> when many pipes are active. Make it so.
>
> Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
Reviewed-by: Mika Kahola <mika.kah...@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_cdclk.c | 40 ++++++++++++++++++++--
> 1 file changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c
> b/drivers/gpu/drm/i915/display/intel_cdclk.c
> index 5fcb393079f7..075ad6055765 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> @@ -1951,6 +1951,25 @@ static bool intel_cdclk_can_crawl(struct
> drm_i915_private *dev_priv,
> a->ref == b->ref;
> }
>
> +static bool intel_cdclk_can_squash(struct drm_i915_private *dev_priv,
> + const struct intel_cdclk_config *a,
> + const struct intel_cdclk_config *b) {
> + /*
> + * FIXME should store a bit more state in intel_cdclk_config
> + * to differentiate squasher vs. cd2x divider properly. For
> + * the moment all platforms with squasher use a fixed cd2x
> + * divider.
> + */
> + if (!has_cdclk_squasher(dev_priv))
> + return false;
> +
> + return a->cdclk != b->cdclk &&
> + a->vco != 0 &&
> + a->vco == b->vco &&
> + a->ref == b->ref;
> +}
> +
> /**
> * intel_cdclk_needs_modeset - Determine if changong between the CDCLK
> * configurations requires a modeset on all pipes
> @@ -1988,7 +2007,17 @@ static bool intel_cdclk_can_cd2x_update(struct
> drm_i915_private *dev_priv,
> if (DISPLAY_VER(dev_priv) < 10 && !IS_BROXTON(dev_priv))
> return false;
>
> + /*
> + * FIXME should store a bit more state in intel_cdclk_config
> + * to differentiate squasher vs. cd2x divider properly. For
> + * the moment all platforms with squasher use a fixed cd2x
> + * divider.
> + */
> + if (has_cdclk_squasher(dev_priv))
> + return false;
> +
> return a->cdclk != b->cdclk &&
> + a->vco != 0 &&
> a->vco == b->vco &&
> a->ref == b->ref;
> }
> @@ -2672,9 +2701,14 @@ int intel_modeset_calc_cdclk(struct
> intel_atomic_state *state)
> pipe = INVALID_PIPE;
> }
>
> - if (intel_cdclk_can_crawl(dev_priv,
> - &old_cdclk_state->actual,
> - &new_cdclk_state->actual)) {
> + if (intel_cdclk_can_squash(dev_priv,
> + &old_cdclk_state->actual,
> + &new_cdclk_state->actual)) {
> + drm_dbg_kms(&dev_priv->drm,
> + "Can change cdclk via squasher\n");
> + } else if (intel_cdclk_can_crawl(dev_priv,
> + &old_cdclk_state->actual,
> + &new_cdclk_state->actual)) {
> drm_dbg_kms(&dev_priv->drm,
> "Can change cdclk via crawl\n");
> } else if (pipe != INVALID_PIPE) {
> --
> 2.27.0
