From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Document what each of the "raw" vs. "optimal" vs. "intermediate"
watermarks do.
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
.../drm/i915/display/intel_display_types.h | 48 ++++++++++---------
1 file changed, 25 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 6b249969c394..b977e70e34d7 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -737,25 +737,34 @@ struct g4x_wm_state {
struct intel_crtc_wm_state {
union {
+ /*
+ * raw:
+ * The "raw" watermark values produced by the formula
+ * given the plane's current state. They do not consider
+ * how much FIFO is actually allocated for each plane.
+ *
+ * optimal:
+ * The "optimal" watermark values given the current
+ * state of the planes and the amount of FIFO
+ * allocated to each, ignoring any previous state
+ * of the planes.
+ *
+ * intermediate:
+ * The "intermediate" watermark values when transitioning
+ * between the old and new "optimal" values. Used when
+ * the watermark registers are single buffered and hence
+ * their state changes asynchronously with regards to the
+ * actual plane registers. These are essentially the
+ * worst case combination of the old and new "optimal"
+ * watermarks, which are therefore safe to use when the
+ * plane is in either its old or new state.
+ */
struct {
- /*
- * Intermediate watermarks; these can be
- * programmed immediately since they satisfy
- * both the current configuration we're
- * switching away from and the new
- * configuration we're switching to.
- */
struct intel_pipe_wm intermediate;
-
- /*
- * Optimal watermarks, programmed post-vblank
- * when this state is committed.
- */
struct intel_pipe_wm optimal;
} ilk;
struct {
- /* "raw" watermarks */
struct skl_pipe_wm raw;
/* gen9+ only needs 1-step wm programming */
struct skl_pipe_wm optimal;
@@ -765,22 +774,15 @@ struct intel_crtc_wm_state {
} skl;
struct {
- /* "raw" watermarks (not inverted) */
- struct g4x_pipe_wm raw[NUM_VLV_WM_LEVELS];
- /* intermediate watermarks (inverted) */
- struct vlv_wm_state intermediate;
- /* optimal watermarks (inverted) */
- struct vlv_wm_state optimal;
- /* display FIFO split */
+ struct g4x_pipe_wm raw[NUM_VLV_WM_LEVELS]; /* not inverted */
+ struct vlv_wm_state intermediate; /* inverted */
+ struct vlv_wm_state optimal; /* inverted */
struct vlv_fifo_state fifo_state;
} vlv;
struct {
- /* "raw" watermarks */
struct g4x_pipe_wm raw[NUM_G4X_WM_LEVELS];
- /* intermediate watermarks */
struct g4x_wm_state intermediate;
- /* optimal watermarks */
struct g4x_wm_state optimal;
} g4x;
};
--
2.26.2
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