[Intel-gfx] [PATCH] drm/i915: Eliminate PIPECONF RMWs from .color_commit()

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Eliminate the PIPECONF RMWs from .comit_commit() so
that we can finally declare the whole vblank evade part
(and the noarm() part) of the pipe commit free of register
reads. Or at least I hope that's the last read...

Only the i9xx/ilk codepaths need this for now, but let's
add the same thing for hsw+ just in case we want to start
calling that during fastsets at some point (eg. to change
dithering settings/etc.).

Should open up the way to start experimenting with
different DSB usage approaches for pipe commits.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_color.c   | 21 ++++----------
 drivers/gpu/drm/i915/display/intel_display.c | 30 ++++++++++++++------
 drivers/gpu/drm/i915/display/intel_display.h |  2 ++
 3 files changed, 29 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
index 34128c9c635c..60532dd0f9f6 100644
--- a/drivers/gpu/drm/i915/display/intel_color.c
+++ b/drivers/gpu/drm/i915/display/intel_color.c
@@ -505,30 +505,19 @@ static void ilk_color_commit_noarm(const struct intel_crtc_state *crtc_state)
 
 static void i9xx_color_commit_arm(const struct intel_crtc_state *crtc_state)
 {
-	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
-	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	enum pipe pipe = crtc->pipe;
-	u32 val;
-
-	val = intel_de_read(dev_priv, PIPECONF(pipe));
-	val &= ~PIPECONF_GAMMA_MODE_MASK_I9XX;
-	val |= PIPECONF_GAMMA_MODE(crtc_state->gamma_mode);
-	intel_de_write(dev_priv, PIPECONF(pipe), val);
+	/* update PIPECONF GAMMA_MODE */
+	i9xx_set_pipeconf(crtc_state);
 }
 
 static void ilk_color_commit_arm(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	enum pipe pipe = crtc->pipe;
-	u32 val;
 
-	val = intel_de_read(dev_priv, PIPECONF(pipe));
-	val &= ~PIPECONF_GAMMA_MODE_MASK_ILK;
-	val |= PIPECONF_GAMMA_MODE(crtc_state->gamma_mode);
-	intel_de_write(dev_priv, PIPECONF(pipe), val);
+	/* update PIPECONF GAMMA_MODE */
+	ilk_set_pipeconf(crtc_state);
 
-	intel_de_write_fw(dev_priv, PIPE_CSC_MODE(pipe),
+	intel_de_write_fw(dev_priv, PIPE_CSC_MODE(crtc->pipe),
 			  crtc_state->csc_mode);
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 29044cf58b87..aa2814332ad9 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -122,8 +122,6 @@
 
 static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_state);
 static void intel_set_pipe_src_size(const struct intel_crtc_state *crtc_state);
-static void i9xx_set_pipeconf(const struct intel_crtc_state *crtc_state);
-static void ilk_set_pipeconf(const struct intel_crtc_state *crtc_state);
 static void hsw_set_transconf(const struct intel_crtc_state *crtc_state);
 static void bdw_set_pipemisc(const struct intel_crtc_state *crtc_state);
 static void ilk_pfit_enable(const struct intel_crtc_state *crtc_state);
@@ -3205,14 +3203,18 @@ static void intel_get_pipe_src_size(struct intel_crtc *crtc,
 	intel_bigjoiner_adjust_pipe_src(pipe_config);
 }
 
-static void i9xx_set_pipeconf(const struct intel_crtc_state *crtc_state)
+void i9xx_set_pipeconf(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	u32 pipeconf = 0;
 
-	/* we keep both pipes enabled on 830 */
-	if (IS_I830(dev_priv))
+	/*
+	 * - We keep both pipes enabled on 830
+	 * - During modeset the pipe is still disabled and must remain so
+	 * - During fastset the pipe is already enabled and must remain so
+	 */
+	if (IS_I830(dev_priv) || !intel_crtc_needs_modeset(crtc_state))
 		pipeconf |= PIPECONF_ENABLE;
 
 	if (crtc_state->double_wide)
@@ -3524,14 +3526,19 @@ static bool i9xx_get_pipe_config(struct intel_crtc *crtc,
 	return ret;
 }
 
-static void ilk_set_pipeconf(const struct intel_crtc_state *crtc_state)
+void ilk_set_pipeconf(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	enum pipe pipe = crtc->pipe;
-	u32 val;
+	u32 val = 0;
 
-	val = 0;
+	/*
+	 * - During modeset the pipe is still disabled and must remain so
+	 * - During fastset the pipe is already enabled and must remain so
+	 */
+	if (!intel_crtc_needs_modeset(crtc_state))
+		val |= PIPECONF_ENABLE;
 
 	switch (crtc_state->pipe_bpp) {
 	case 18:
@@ -3589,6 +3596,13 @@ static void hsw_set_transconf(const struct intel_crtc_state *crtc_state)
 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
 	u32 val = 0;
 
+	/*
+	 * - During modeset the pipe is still disabled and must remain so
+	 * - During fastset the pipe is already enabled and must remain so
+	 */
+	if (!intel_crtc_needs_modeset(crtc_state))
+		val |= PIPECONF_ENABLE;
+
 	if (IS_HASWELL(dev_priv) && crtc_state->dither)
 		val |= PIPECONF_DITHER_EN | PIPECONF_DITHER_TYPE_SP;
 
diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
index 867fa248f042..ee488205c5fe 100644
--- a/drivers/gpu/drm/i915/display/intel_display.h
+++ b/drivers/gpu/drm/i915/display/intel_display.h
@@ -561,6 +561,8 @@ u8 intel_crtc_bigjoiner_slave_pipes(const struct intel_crtc_state *crtc_state);
 struct intel_crtc *intel_master_crtc(const struct intel_crtc_state *crtc_state);
 
 void intel_plane_destroy(struct drm_plane *plane);
+void i9xx_set_pipeconf(const struct intel_crtc_state *crtc_state);
+void ilk_set_pipeconf(const struct intel_crtc_state *crtc_state);
 void intel_enable_transcoder(const struct intel_crtc_state *new_crtc_state);
 void intel_disable_transcoder(const struct intel_crtc_state *old_crtc_state);
 void i830_enable_pipe(struct drm_i915_private *dev_priv, enum pipe pipe);
-- 
2.35.1