Although we can do a good job of reading out hardware state, the
graphics firmware may have programmed the watermarks in a creative way
that doesn't match how i915 would have chosen to program them. We
shouldn't trust the firmware's watermark programming, but should rather
re-calculate how we think WM's should be programmed and then shove those
values into the hardware.
We can do this pretty easily by creating a dummy top-level state,
running it through the check process to calculate all the values, and
then just programming the watermarks for each CRTC.
v2: Move watermark sanitization after our BIOS fb reconstruction; the
watermark calculations that we do here need to look at pstate->fb,
which isn't setup yet in intel_modeset_setup_hw_state(), even
though we have an enabled & visible plane.
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
---
drivers/gpu/drm/drm_atomic_helper.c | 1 +
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/intel_display.c | 58 ++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_pm.c | 14 +++++----
4 files changed, 68 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 3731a26..8a98e0c 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2478,6 +2478,7 @@ drm_atomic_helper_duplicate_state(struct drm_device *dev,
}
}
+ drm_modeset_lock(&dev->mode_config.connection_mutex, ctx);
drm_for_each_connector(conn, dev) {
struct drm_connector_state *conn_state;
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 11ae5a5..5172604 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -630,6 +630,7 @@ struct drm_i915_display_funcs {
struct dpll *best_clock);
int (*compute_pipe_wm)(struct intel_crtc *crtc,
struct drm_atomic_state *state);
+ void (*program_watermarks)(struct intel_crtc_state *cstate);
void (*update_wm)(struct drm_crtc *crtc);
int (*modeset_calc_cdclk)(struct drm_atomic_state *state);
void (*modeset_commit_cdclk)(struct drm_atomic_state *state);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 00e4c37..eb52afa 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15120,6 +15120,57 @@ void intel_modeset_init_hw(struct drm_device *dev)
intel_enable_gt_powersave(dev);
}
+/*
+ * Calculate what we think the watermarks should be for the state we've read
+ * out of the hardware and then immediately program those watermarks so that
+ * we ensure the hardware settings match our internal state.
+ */
+static void sanitize_watermarks(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = to_i915(dev);
+ struct drm_atomic_state *state;
+ struct drm_crtc *crtc;
+ struct drm_crtc_state *cstate;
+ struct drm_modeset_acquire_ctx ctx;
+ int ret;
+ int i;
+
+ /* Only supported on platforms that use atomic watermark design */
+ if (!dev_priv->display.program_watermarks)
+ return;
+
+ /*
+ * Calculate what we think WM's should be by creating a dummy state and
+ * running it through the atomic check code.
+ */
+ drm_modeset_acquire_init(&ctx, 0);
+ state = drm_atomic_helper_duplicate_state(dev, &ctx);
+ if (WARN_ON(IS_ERR(state)))
+ return;
+
+ ret = intel_atomic_check(dev, state);
+ if (ret) {
+ /*
+ * Just give up and leave watermarks untouched if we get an
+ * error back from 'check'
+ */
+ DRM_DEBUG_KMS("Could not determine valid watermarks for inherited state\n");
+ return;
+ }
+
+ /* Write calculated watermark values back */
+ to_i915(dev)->wm.config = to_intel_atomic_state(state)->wm_config;
+ 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);
+ }
+
+ drm_atomic_state_free(state);
+ drm_modeset_drop_locks(&ctx);
+ drm_modeset_acquire_fini(&ctx);
+}
+
void intel_modeset_init(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -15243,6 +15294,13 @@ void intel_modeset_init(struct drm_device *dev)
intel_dump_pipe_config(crtc, crtc->config,
"[state after init fb reconstruction]");
}
+
+ /*
+ * Make sure hardware watermarks really match the state we read out.
+ * Note that we need to do this after reconstructing the BIOS fb's
+ * since the watermark calculation done here will use pstate->fb.
+ */
+ sanitize_watermarks(dev);
}
static void intel_enable_pipe_a(struct drm_device *dev)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d4cd5d5..c209a69 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3610,15 +3610,19 @@ static void skl_update_wm(struct drm_crtc *crtc)
dev_priv->wm.skl_hw = *results;
}
-static void ilk_program_watermarks(struct drm_i915_private *dev_priv)
+static void ilk_program_watermarks(struct intel_crtc_state *cstate)
{
- struct drm_device *dev = dev_priv->dev;
+ struct drm_crtc *crtc = cstate->base.crtc;
+ struct drm_device *dev = crtc->dev;
+ struct drm_i915_private *dev_priv = to_i915(dev);
struct intel_pipe_wm lp_wm_1_2 = {}, lp_wm_5_6 = {}, *best_lp_wm;
struct ilk_wm_maximums max;
struct intel_wm_config *config = &dev_priv->wm.config;
struct ilk_wm_values results = {};
enum intel_ddb_partitioning partitioning;
+ to_intel_crtc(crtc)->wm.active.ilk = cstate->wm.optimal.ilk;
+
ilk_compute_wm_maximums(dev, 1, config, INTEL_DDB_PART_1_2, &max);
ilk_wm_merge(dev, config, &max, &lp_wm_1_2);
@@ -3643,7 +3647,6 @@ static void ilk_program_watermarks(struct drm_i915_private *dev_priv)
static void ilk_update_wm(struct drm_crtc *crtc)
{
- struct drm_i915_private *dev_priv = to_i915(crtc->dev);
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
struct intel_crtc_state *cstate = to_intel_crtc_state(crtc->state);
@@ -3661,9 +3664,7 @@ static void ilk_update_wm(struct drm_crtc *crtc)
intel_wait_for_vblank(crtc->dev, intel_crtc->pipe);
}
- intel_crtc->wm.active.ilk = cstate->wm.optimal.ilk;
-
- ilk_program_watermarks(dev_priv);
+ ilk_program_watermarks(cstate);
}
static void skl_pipe_wm_active_state(uint32_t val,
@@ -6971,6 +6972,7 @@ void intel_init_pm(struct drm_device *dev)
dev_priv->wm.spr_latency[0] && dev_priv->wm.cur_latency[0])) {
dev_priv->display.update_wm = ilk_update_wm;
dev_priv->display.compute_pipe_wm = ilk_compute_pipe_wm;
+ dev_priv->display.program_watermarks = ilk_program_watermarks;
} else {
DRM_DEBUG_KMS("Failed to read display plane latency. "
"Disable CxSR\n");
--
2.1.4
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