Re: [PATCH v2 4/4] drm/i915: Calculate vlv/chv intermediate watermarks correctly, v2.

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, May 03, 2017 at 04:06:37PM +0200, Maarten Lankhorst wrote:
> Op 03-05-17 om 15:45 schreef Ville Syrjälä:
> > On Mon, May 01, 2017 at 03:34:34PM +0200, Maarten Lankhorst wrote:
> >> The watermarks it should calculate against are the old optimal watermarks.
> >> The currently active crtc watermarks are pure fiction, and are invalid in
> >> case of a nonblocking modeset, page flip enabling/disabling planes or any
> >> other reason.
> >>
> >> When the crtc is disabled or during a modeset the intermediate watermarks
> >> don't need to be programmed separately, and could be directly assigned
> >> to the optimal watermarks.
> >>
> >> Also rename crtc_state to new_crtc_state, to distinguish it from the old state.
> >>
> >> Changes since v1:
> >> - Use intel_atomic_get_old_crtc_state. (ville)
> >>
> >> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/intel_pm.c | 20 ++++++++++++++------
> >>  1 file changed, 14 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> >> index 0f344b1fff45..a09396ee1f3d 100644
> >> --- a/drivers/gpu/drm/i915/intel_pm.c
> >> +++ b/drivers/gpu/drm/i915/intel_pm.c
> >> @@ -1458,16 +1458,24 @@ static void vlv_atomic_update_fifo(struct intel_atomic_state *state,
> >>  
> >>  static int vlv_compute_intermediate_wm(struct drm_device *dev,
> >>  				       struct intel_crtc *crtc,
> >> -				       struct intel_crtc_state *crtc_state)
> >> +				       struct intel_crtc_state *new_crtc_state)
> >>  {
> >> -	struct vlv_wm_state *intermediate = &crtc_state->wm.vlv.intermediate;
> >> -	const struct vlv_wm_state *optimal = &crtc_state->wm.vlv.optimal;
> >> -	const struct vlv_wm_state *active = &crtc->wm.active.vlv;
> >> +	struct vlv_wm_state *intermediate = &new_crtc_state->wm.vlv.intermediate;
> >> +	const struct vlv_wm_state *optimal = &new_crtc_state->wm.vlv.optimal;
> >> +	const struct intel_crtc_state *old_crtc_state =
> >> +		intel_atomic_get_old_crtc_state(new_crtc_state->base.state, crtc);
> >> +	const struct vlv_wm_state *active = &old_crtc_state->wm.vlv.optimal;
> >>  	int level;
> >>  
> >> +	if (!new_crtc_state->base.active || drm_atomic_crtc_needs_modeset(&new_crtc_state->base)) {
> >> +		*intermediate = *optimal;
> >> +
> >> +		return 0;
> >> +	}
> >> +
> >>  	intermediate->num_levels = min(optimal->num_levels, active->num_levels);
> >>  	intermediate->cxsr = optimal->cxsr && active->cxsr &&
> >> -		!crtc_state->disable_cxsr;
> >> +		!new_crtc_state->disable_cxsr;
> > We need to consider disable_cxsr even in the modeset case.
> Why is this? crtc_state->disable_cxsr is set if any plane is part of the crtc during modeset, so it's disabled during modeset already.

It's set if any plane is enabling/disabling, which should be quite
typical during a modeset.

-- 
Ville Syrjälä
Intel OTC
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