drm/i915: Allow preservation of watermarks, v2.

As Paulo has noted we can help bisectability by separating computing
watermarks on a noop in 2 separate commits.

This patch no longer clears the crtc watermark state, but recalculates
it completely. Regardless whether a level is used the full values for
each level are calculated. If a level is invalid wm[level].enable is
unset.

Changes since v1:
- Only call ilk_validate_wm_level when level <= usable_level. (Ville)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/56D6D09E.5040007@linux.intel.com
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 7df5a63..161c66b 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2300,7 +2300,7 @@ static int ilk_compute_pipe_wm(struct intel_crtc *intel_crtc,
        struct intel_plane_state *pristate = NULL;
        struct intel_plane_state *sprstate = NULL;
        struct intel_plane_state *curstate = NULL;
-       int level, max_level = ilk_wm_max_level(dev);
+       int level, max_level = ilk_wm_max_level(dev), usable_level;
        struct ilk_wm_maximums max;
 
        cstate = intel_atomic_get_crtc_state(state, intel_crtc);
@@ -2308,7 +2308,6 @@ static int ilk_compute_pipe_wm(struct intel_crtc *intel_crtc,
                return PTR_ERR(cstate);
 
        pipe_wm = &cstate->wm.optimal.ilk;
-       memset(pipe_wm, 0, sizeof(*pipe_wm));
 
        for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane) {
                ps = drm_atomic_get_plane_state(state,
@@ -2330,13 +2329,15 @@ static int ilk_compute_pipe_wm(struct intel_crtc *intel_crtc,
                (drm_rect_width(&sprstate->dst) != drm_rect_width(&sprstate->src) >> 16 ||
                drm_rect_height(&sprstate->dst) != drm_rect_height(&sprstate->src) >> 16);
 
+       usable_level = max_level;
+
        /* ILK/SNB: LP2+ watermarks only w/o sprites */
        if (INTEL_INFO(dev)->gen <= 6 && sprstate->visible)
-               max_level = 1;
+               usable_level = 1;
 
        /* ILK/SNB/IVB: LP1+ watermarks only w/o scaling */
        if (pipe_wm->sprites_scaled)
-               max_level = 0;
+               usable_level = 0;
 
        ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate,
                             pristate, sprstate, curstate, &pipe_wm->wm[0]);
@@ -2350,20 +2351,22 @@ static int ilk_compute_pipe_wm(struct intel_crtc *intel_crtc,
        ilk_compute_wm_reg_maximums(dev, 1, &max);
 
        for (level = 1; level <= max_level; level++) {
-               struct intel_wm_level wm = {};
+               struct intel_wm_level *wm = &pipe_wm->wm[level];
 
                ilk_compute_wm_level(dev_priv, intel_crtc, level, cstate,
-                                    pristate, sprstate, curstate, &wm);
+                                    pristate, sprstate, curstate, wm);
 
                /*
                 * Disable any watermark level that exceeds the
                 * register maximums since such watermarks are
                 * always invalid.
                 */
-               if (!ilk_validate_wm_level(level, &max, &wm))
-                       break;
-
-               pipe_wm->wm[level] = wm;
+               if (level > usable_level) {
+                       wm->enable = false;
+               } else if (!ilk_validate_wm_level(level, &max, wm)) {
+                       wm->enable = false;
+                       usable_level = level;
+               }
        }
 
        return 0;