drm/i915: Add two-stage ILK-style watermark programming (v11)
In addition to calculating final watermarks, let's also pre-calculate a
set of intermediate watermark values at atomic check time. These
intermediate watermarks are a combination of the watermarks for the old
state and the new state; they should satisfy the requirements of both
states which means they can be programmed immediately when we commit the
atomic state (without waiting for a vblank). Once the vblank does
happen, we can then re-program watermarks to the more optimal final
value.
v2: Significant rebasing/rewriting.
v3:
- Move 'need_postvbl_update' flag to CRTC state (Daniel)
- Don't forget to check intermediate watermark values for validity
(Maarten)
- Don't due async watermark optimization; just do it at the end of the
atomic transaction, after waiting for vblanks. We do want it to be
async eventually, but adding that now will cause more trouble for
Maarten's in-progress work. (Maarten)
- Don't allocate space in crtc_state for intermediate watermarks on
platforms that don't need it (gen9+).
- Move WaCxSRDisabledForSpriteScaling:ivb into intel_begin_crtc_commit
now that ilk_update_wm is gone.
v4:
- Add a wm_mutex to cover updates to intel_crtc->active and the
need_postvbl_update flag. Since we don't have async yet it isn't
terribly important yet, but might as well add it now.
- Change interface to program watermarks. Platforms will now expose
.initial_watermarks() and .optimize_watermarks() functions to do
watermark programming. These should lock wm_mutex, copy the
appropriate state values into intel_crtc->active, and then call
the internal program watermarks function.
v5:
- Skip intermediate watermark calculation/check during initial hardware
readout since we don't trust the existing HW values (and don't have
valid values of our own yet).
- Don't try to call .optimize_watermarks() on platforms that don't have
atomic watermarks yet. (Maarten)
v6:
- Rebase
v7:
- Further rebase
v8:
- A few minor indentation and line length fixes
v9:
- Yet another rebase since Maarten's patches reworked a bunch of the
code (wm_pre, wm_post, etc.) that this was previously based on.
v10:
- Move wm_mutex to dev_priv to protect against racing commits against
disjoint CRTC sets. (Maarten)
- Drop unnecessary clearing of cstate->wm.need_postvbl_update (Maarten)
v11:
- Now that we've moved to atomic watermark updates, make sure we call
the proper function to program watermarks in
{ironlake,haswell}_crtc_enable(); the failure to do so on the
previous patch iteration led to us not actually programming the
watermarks before turning on the CRTC, which was the cause of the
underruns that the CI system was seeing.
- Fix inverted logic for determining when to optimize watermarks. We
were needlessly optimizing when the intermediate/optimal values were
the same (harmless), but not actually optimizing when they differed
(also harmless, but wasteful from a power/bandwidth perspective).
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1456276813-5689-1-git-send-email-matthew.d.roper@intel.com
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8b7b8b6..79bf527 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4843,7 +4843,42 @@
intel_set_memory_cxsr(dev_priv, false);
}
- if (!needs_modeset(&pipe_config->base) && pipe_config->wm_changed)
+ /*
+ * 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 (pipe_config->disable_lp_wm) {
+ ilk_disable_lp_wm(dev);
+ intel_wait_for_vblank(dev, crtc->pipe);
+ }
+
+ /*
+ * If we're doing a modeset, we're done. No need to do any pre-vblank
+ * watermark programming here.
+ */
+ if (needs_modeset(&pipe_config->base))
+ return;
+
+ /*
+ * For platforms that support atomic watermarks, program the
+ * 'intermediate' watermarks immediately. On pre-gen9 platforms, these
+ * will be the intermediate values that are safe for both pre- and
+ * post- vblank; when vblank happens, the 'active' values will be set
+ * to the final 'target' values and we'll do this again to get the
+ * optimal watermarks. For gen9+ platforms, the values we program here
+ * will be the final target values which will get automatically latched
+ * at vblank time; no further programming will be necessary.
+ *
+ * If a platform hasn't been transitioned to atomic watermarks yet,
+ * we'll continue to update watermarks the old way, if flags tell
+ * us to.
+ */
+ if (dev_priv->display.initial_watermarks != NULL)
+ dev_priv->display.initial_watermarks(pipe_config);
+ else if (pipe_config->wm_changed)
intel_update_watermarks(&crtc->base);
}
@@ -4922,7 +4957,7 @@
*/
intel_crtc_load_lut(crtc);
- intel_update_watermarks(crtc);
+ dev_priv->display.initial_watermarks(intel_crtc->config);
intel_enable_pipe(intel_crtc);
if (intel_crtc->config->has_pch_encoder)
@@ -5021,7 +5056,7 @@
if (!intel_crtc->config->has_dsi_encoder)
intel_ddi_enable_transcoder_func(crtc);
- intel_update_watermarks(crtc);
+ dev_priv->display.initial_watermarks(pipe_config);
intel_enable_pipe(intel_crtc);
if (intel_crtc->config->has_pch_encoder)
@@ -11785,6 +11820,7 @@
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
struct drm_plane *plane = plane_state->plane;
struct drm_device *dev = crtc->dev;
+ struct drm_i915_private *dev_priv = to_i915(dev);
struct intel_plane_state *old_plane_state =
to_intel_plane_state(plane->state);
int idx = intel_crtc->base.base.id, ret;
@@ -11843,6 +11879,11 @@
pipe_config->wm_changed = true;
}
+ /* Pre-gen9 platforms need two-step watermark updates */
+ if (pipe_config->wm_changed && INTEL_INFO(dev)->gen < 9 &&
+ dev_priv->display.optimize_watermarks)
+ to_intel_crtc_state(crtc_state)->wm.need_postvbl_update = true;
+
if (visible || was_visible)
intel_crtc->atomic.fb_bits |=
to_intel_plane(plane)->frontbuffer_bit;
@@ -11954,8 +11995,29 @@
ret = 0;
if (dev_priv->display.compute_pipe_wm) {
ret = dev_priv->display.compute_pipe_wm(intel_crtc, state);
- if (ret)
+ if (ret) {
+ DRM_DEBUG_KMS("Target pipe watermarks are invalid\n");
return ret;
+ }
+ }
+
+ if (dev_priv->display.compute_intermediate_wm &&
+ !to_intel_atomic_state(state)->skip_intermediate_wm) {
+ if (WARN_ON(!dev_priv->display.compute_pipe_wm))
+ return 0;
+
+ /*
+ * Calculate 'intermediate' watermarks that satisfy both the
+ * old state and the new state. We can program these
+ * immediately.
+ */
+ ret = dev_priv->display.compute_intermediate_wm(crtc->dev,
+ intel_crtc,
+ pipe_config);
+ if (ret) {
+ DRM_DEBUG_KMS("No valid intermediate pipe watermarks are possible\n");
+ return ret;
+ }
}
if (INTEL_INFO(dev)->gen >= 9) {
@@ -13488,6 +13550,7 @@
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_crtc_state *crtc_state;
struct drm_crtc *crtc;
+ struct intel_crtc_state *intel_cstate;
int ret = 0, i;
bool hw_check = intel_state->modeset;
unsigned long put_domains[I915_MAX_PIPES] = {};
@@ -13603,6 +13666,20 @@
if (intel_state->modeset)
intel_display_power_put(dev_priv, POWER_DOMAIN_MODESET);
+ /*
+ * Now that the vblank has passed, we can go ahead and program the
+ * optimal watermarks on platforms that need two-step watermark
+ * programming.
+ *
+ * TODO: Move this (and other cleanup) to an async worker eventually.
+ */
+ for_each_crtc_in_state(state, crtc, crtc_state, i) {
+ intel_cstate = to_intel_crtc_state(crtc->state);
+
+ if (dev_priv->display.optimize_watermarks)
+ dev_priv->display.optimize_watermarks(intel_cstate);
+ }
+
mutex_lock(&dev->struct_mutex);
drm_atomic_helper_cleanup_planes(dev, state);
mutex_unlock(&dev->struct_mutex);
@@ -15273,7 +15350,7 @@
int i;
/* Only supported on platforms that use atomic watermark design */
- if (!dev_priv->display.program_watermarks)
+ if (!dev_priv->display.optimize_watermarks)
return;
/*
@@ -15294,6 +15371,13 @@
if (WARN_ON(IS_ERR(state)))
goto fail;
+ /*
+ * Hardware readout is the only time we don't want to calculate
+ * intermediate watermarks (since we don't trust the current
+ * watermarks).
+ */
+ to_intel_atomic_state(state)->skip_intermediate_wm = true;
+
ret = intel_atomic_check(dev, state);
if (ret) {
/*
@@ -15316,7 +15400,8 @@
for_each_crtc_in_state(state, crtc, cstate, i) {
struct intel_crtc_state *cs = to_intel_crtc_state(cstate);
- dev_priv->display.program_watermarks(cs);
+ cs->wm.need_postvbl_update = true;
+ dev_priv->display.optimize_watermarks(cs);
}
drm_atomic_state_free(state);