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

[Maarten Lankhorst]

Op 03-05-17 om 16:11 schreef Ville Syrjälä:
> 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 at 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.

Yeah but .initial_watermarks is called during crtc_enable, so cxsr will get enabled anyway.

Maybe I'm missing something, but why are the intermediate watermarks and optimize_watermarks needed here?

~Maarten