drm/i915: Try to fix the messy IVB sprite scaling workaround
We now have a very clear method of disabling LP1+ wartermarks,
and we can actually detect if we actually did disable them, or
if they were already disabled. Use that to clean up the
WaCxSRDisabledForSpriteScaling:ivb handling.
I was hoping to apply the workaround in a way that wouldn't
require a blocking wait, but sadly IVB really does appear to
require LP1+ watermarks to be off for an entire frame before
enabling sprite scaling. Simply disabling LP1+ watermarks
during the previous frame is not enough, no matter how early
in the frame we do it :(
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 7e02834..ecdb64e 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2426,6 +2426,36 @@
return dirty;
}
+static bool _ilk_disable_lp_wm(struct drm_i915_private *dev_priv,
+ unsigned int dirty)
+{
+ struct hsw_wm_values *previous = &dev_priv->wm.hw;
+ bool changed = false;
+
+ if (dirty & WM_DIRTY_LP(3) && previous->wm_lp[2] & WM1_LP_SR_EN) {
+ previous->wm_lp[2] &= ~WM1_LP_SR_EN;
+ I915_WRITE(WM3_LP_ILK, previous->wm_lp[2]);
+ changed = true;
+ }
+ if (dirty & WM_DIRTY_LP(2) && previous->wm_lp[1] & WM1_LP_SR_EN) {
+ previous->wm_lp[1] &= ~WM1_LP_SR_EN;
+ I915_WRITE(WM2_LP_ILK, previous->wm_lp[1]);
+ changed = true;
+ }
+ if (dirty & WM_DIRTY_LP(1) && previous->wm_lp[0] & WM1_LP_SR_EN) {
+ previous->wm_lp[0] &= ~WM1_LP_SR_EN;
+ I915_WRITE(WM1_LP_ILK, previous->wm_lp[0]);
+ changed = true;
+ }
+
+ /*
+ * Don't touch WM1S_LP_EN here.
+ * Doing so could cause underruns.
+ */
+
+ return changed;
+}
+
/*
* The spec says we shouldn't write when we don't need, because every write
* causes WMs to be re-evaluated, expending some power.
@@ -2438,27 +2468,11 @@
unsigned int dirty;
uint32_t val;
- dirty = ilk_compute_wm_dirty(dev_priv->dev, previous, results);
+ dirty = ilk_compute_wm_dirty(dev, previous, results);
if (!dirty)
return;
- if (dirty & WM_DIRTY_LP(3) && previous->wm_lp[2] & WM1_LP_SR_EN) {
- previous->wm_lp[2] &= ~WM1_LP_SR_EN;
- I915_WRITE(WM3_LP_ILK, previous->wm_lp[2]);
- }
- if (dirty & WM_DIRTY_LP(2) && previous->wm_lp[1] & WM1_LP_SR_EN) {
- previous->wm_lp[1] &= ~WM1_LP_SR_EN;
- I915_WRITE(WM2_LP_ILK, previous->wm_lp[1]);
- }
- if (dirty & WM_DIRTY_LP(1) && previous->wm_lp[0] & WM1_LP_SR_EN) {
- previous->wm_lp[0] &= ~WM1_LP_SR_EN;
- I915_WRITE(WM1_LP_ILK, previous->wm_lp[0]);
- }
-
- /*
- * Don't touch WM1S_LP_EN here.
- * Doing so could cause underruns.
- */
+ _ilk_disable_lp_wm(dev_priv, dirty);
if (dirty & WM_DIRTY_PIPE(PIPE_A))
I915_WRITE(WM0_PIPEA_ILK, results->wm_pipe[0]);
@@ -2523,6 +2537,13 @@
dev_priv->wm.hw = *results;
}
+static bool ilk_disable_lp_wm(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ return _ilk_disable_lp_wm(dev_priv, WM_DIRTY_LP_ALL);
+}
+
static void haswell_update_wm(struct drm_crtc *crtc)
{
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
@@ -2572,6 +2593,7 @@
uint32_t sprite_width, int pixel_size,
bool enabled, bool scaled)
{
+ struct drm_device *dev = plane->dev;
struct intel_plane *intel_plane = to_intel_plane(plane);
intel_plane->wm.enabled = enabled;
@@ -2579,6 +2601,16 @@
intel_plane->wm.horiz_pixels = sprite_width;
intel_plane->wm.bytes_per_pixel = pixel_size;
+ /*
+ * IVB workaround: must disable low power watermarks for at least
+ * one frame before enabling scaling. LP watermarks can be re-enabled
+ * when scaling is disabled.
+ *
+ * WaCxSRDisabledForSpriteScaling:ivb
+ */
+ if (IS_IVYBRIDGE(dev) && scaled && ilk_disable_lp_wm(dev))
+ intel_wait_for_vblank(dev, intel_plane->pipe);
+
haswell_update_wm(crtc);
}