Re: [PATCH 1/2] drm/i915: Do not rely on wm preservation for ILK watermarks

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

On Thu, Oct 19, 2017 at 05:13:40PM +0200, Maarten Lankhorst wrote:
> The original intent was to preserve watermarks as much as possible
> in intel_pipe_wm.raw_wm, and put the validated ones in intel_pipe_wm.wm.
> 
> It seems this approach is insufficient and we don't always preserve
> the raw watermarks, so just use the atomic iterator we're already using
> to get a const pointer to all bound planes on the crtc.

I don't really like that trick. But I gave this series a try on my IVB
and so far things seem to work correctly. IIRC just patch 2 (or something
similar) alone resulted in failure to compute intermediate watermarks
and thus a black screen.

So if it fixes things
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102373
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: stable@vger.kernel.org #v4.8+
> ---
>  drivers/gpu/drm/i915/intel_drv.h |  1 -
>  drivers/gpu/drm/i915/intel_pm.c  | 51 +++++++++++++++++-----------------------
>  2 files changed, 21 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 47d022d48718..7bc60c848940 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -499,7 +499,6 @@ struct intel_crtc_scaler_state {
>  
>  struct intel_pipe_wm {
>  	struct intel_wm_level wm[5];
> -	struct intel_wm_level raw_wm[5];
>  	uint32_t linetime;
>  	bool fbc_wm_enabled;
>  	bool pipe_enabled;
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index c42a65a93b3a..ea70c720f492 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -2721,9 +2721,9 @@ static void ilk_compute_wm_level(const struct drm_i915_private *dev_priv,
>  				 const struct intel_crtc *intel_crtc,
>  				 int level,
>  				 struct intel_crtc_state *cstate,
> -				 struct intel_plane_state *pristate,
> -				 struct intel_plane_state *sprstate,
> -				 struct intel_plane_state *curstate,
> +				 const struct intel_plane_state *pristate,
> +				 const struct intel_plane_state *sprstate,
> +				 const struct intel_plane_state *curstate,
>  				 struct intel_wm_level *result)
>  {
>  	uint16_t pri_latency = dev_priv->wm.pri_latency[level];
> @@ -3043,28 +3043,24 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
>  	struct intel_pipe_wm *pipe_wm;
>  	struct drm_device *dev = state->dev;
>  	const struct drm_i915_private *dev_priv = to_i915(dev);
> -	struct intel_plane *intel_plane;
> -	struct intel_plane_state *pristate = NULL;
> -	struct intel_plane_state *sprstate = NULL;
> -	struct intel_plane_state *curstate = NULL;
> +	struct drm_plane *plane;
> +	const struct drm_plane_state *plane_state;
> +	const struct intel_plane_state *pristate = NULL;
> +	const struct intel_plane_state *sprstate = NULL;
> +	const struct intel_plane_state *curstate = NULL;
>  	int level, max_level = ilk_wm_max_level(dev_priv), usable_level;
>  	struct ilk_wm_maximums max;
>  
>  	pipe_wm = &cstate->wm.ilk.optimal;
>  
> -	for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane) {
> -		struct intel_plane_state *ps;
> -
> -		ps = intel_atomic_get_existing_plane_state(state,
> -							   intel_plane);
> -		if (!ps)
> -			continue;
> +	drm_atomic_crtc_state_for_each_plane_state(plane, plane_state, &cstate->base) {
> +		const struct intel_plane_state *ps = to_intel_plane_state(plane_state);
>  
> -		if (intel_plane->base.type == DRM_PLANE_TYPE_PRIMARY)
> +		if (plane->type == DRM_PLANE_TYPE_PRIMARY)
>  			pristate = ps;
> -		else if (intel_plane->base.type == DRM_PLANE_TYPE_OVERLAY)
> +		else if (plane->type == DRM_PLANE_TYPE_OVERLAY)
>  			sprstate = ps;
> -		else if (intel_plane->base.type == DRM_PLANE_TYPE_CURSOR)
> +		else if (plane->type == DRM_PLANE_TYPE_CURSOR)
>  			curstate = ps;
>  	}
>  
> @@ -3086,11 +3082,9 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
>  	if (pipe_wm->sprites_scaled)
>  		usable_level = 0;
>  
> -	ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate,
> -			     pristate, sprstate, curstate, &pipe_wm->raw_wm[0]);
> -
>  	memset(&pipe_wm->wm, 0, sizeof(pipe_wm->wm));
> -	pipe_wm->wm[0] = pipe_wm->raw_wm[0];
> +	ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate,
> +			     pristate, sprstate, curstate, &pipe_wm->wm[0]);
>  
>  	if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
>  		pipe_wm->linetime = hsw_compute_linetime_wm(cstate);
> @@ -3100,8 +3094,8 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
>  
>  	ilk_compute_wm_reg_maximums(dev_priv, 1, &max);
>  
> -	for (level = 1; level <= max_level; level++) {
> -		struct intel_wm_level *wm = &pipe_wm->raw_wm[level];
> +	for (level = 1; level <= usable_level; level++) {
> +		struct intel_wm_level *wm = &pipe_wm->wm[level];
>  
>  		ilk_compute_wm_level(dev_priv, intel_crtc, level, cstate,
>  				     pristate, sprstate, curstate, wm);
> @@ -3111,13 +3105,10 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
>  		 * register maximums since such watermarks are
>  		 * always invalid.
>  		 */
> -		if (level > usable_level)
> -			continue;
> -
> -		if (ilk_validate_wm_level(level, &max, wm))
> -			pipe_wm->wm[level] = *wm;
> -		else
> -			usable_level = level;
> +		if (!ilk_validate_wm_level(level, &max, wm)) {
> +			memset(wm, 0, sizeof(*wm));
> +			break;
> +		}
>  	}
>  
>  	return 0;
> -- 
> 2.14.1

-- 
Ville Syrjälä
Intel OTC
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