[Intel-gfx] [PATCH 2/2] drm/i915: dynamic Haswell display power well support

[Paulo Zanoni]

From: Daniel Vetter <daniel.vetter at ffwll.ch>

We can disable (almost) all the display hw if we only use pipe A, with
the integrated edp transcoder on port A. Because we don't set the cpu
transcoder that early (yet), we need to help us with a trick to simply
check for any edp encoders.

And wrt the old code: Can anyone explain what that struct mutex
grabbing was supposed to protect?

v2: Paulo Zanoni pointed out that we also need to configure the eDP
cpu transcoder correctly.

v3: Made by Paulo Zanoni
  - Rebase patch to be on top of "fix intel_init_power_wells" patch
  - Fix typos
  - Fix a small bug by adding a "connectors_active" check
  - Restore the initial code that unconditionally enables the power
    well when taking over from the BIOS

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c     |  8 +++++++-
 drivers/gpu/drm/i915/intel_display.c | 31 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h     |  1 +
 drivers/gpu/drm/i915/intel_pm.c      |  2 +-
 4 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index f02b3fe..fd01e95 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -960,7 +960,13 @@ void intel_ddi_enable_pipe_func(struct drm_crtc *crtc)
 	if (cpu_transcoder == TRANSCODER_EDP) {
 		switch (pipe) {
 		case PIPE_A:
-			temp |= TRANS_DDI_EDP_INPUT_A_ONOFF;
+			/* Can only use the always-on power well for eDP when
+			 * not using the panel fitter, and when not using motion
+			 * blur mitigation (which we don't support). */
+			if (dev_priv->pch_pf_size)
+				temp |= TRANS_DDI_EDP_INPUT_A_ONOFF;
+			else
+				temp |= TRANS_DDI_EDP_INPUT_A_ON;
 			break;
 		case PIPE_B:
 			temp |= TRANS_DDI_EDP_INPUT_B_ONOFF;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 1864b4f..65dd930 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5449,6 +5449,35 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
 	return fdi_config_ok ? ret : -EINVAL;
 }
 
+static void haswell_modeset_global_resources(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	bool enable = false;
+	struct intel_crtc *crtc;
+	struct intel_encoder *encoder;
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, base.head) {
+		if (crtc->pipe != PIPE_A && crtc->base.enabled)
+			enable = true;
+		/* XXX: Should check for edp transcoder here, but thanks to init
+		 * sequence that's not yet availble. Just in case desktop eDP on
+		 * PORT D is possible on haswell, too. */
+	}
+
+	list_for_each_entry(encoder, &dev->mode_config.encoder_list,
+			    base.head) {
+		if (encoder->type != INTEL_OUTPUT_EDP &&
+		    encoder->connectors_active)
+			enable = true;
+	}
+
+	/* Even the eDP panel fitter is outside the always-on well. */
+	if (dev_priv->pch_pf_size)
+		enable = true;
+
+	intel_set_power_well(dev, enable);
+}
+
 static int haswell_crtc_mode_set(struct drm_crtc *crtc,
 				 struct drm_display_mode *mode,
 				 struct drm_display_mode *adjusted_mode,
@@ -8422,6 +8451,8 @@ static void intel_init_display(struct drm_device *dev)
 		} else if (IS_HASWELL(dev)) {
 			dev_priv->display.fdi_link_train = hsw_fdi_link_train;
 			dev_priv->display.write_eld = haswell_write_eld;
+			dev_priv->display.modeset_global_resources =
+				haswell_modeset_global_resources;
 		} else
 			dev_priv->display.update_wm = NULL;
 	} else if (IS_G4X(dev)) {
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 6bafe26..6355822 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -647,6 +647,7 @@ extern void intel_gpu_ips_init(struct drm_i915_private *dev_priv);
 extern void intel_gpu_ips_teardown(void);
 
 extern void intel_init_power_well(struct drm_device *dev);
+extern void intel_set_power_well(struct drm_device *dev, bool enable);
 extern void intel_enable_gt_powersave(struct drm_device *dev);
 extern void intel_disable_gt_powersave(struct drm_device *dev);
 extern void gen6_gt_check_fifodbg(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 53a44e0..beceb38 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3919,7 +3919,7 @@ void intel_init_clock_gating(struct drm_device *dev)
 	dev_priv->display.init_clock_gating(dev);
 }
 
-static void intel_set_power_well(struct drm_device *dev, bool enable)
+void intel_set_power_well(struct drm_device *dev, bool enable)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	bool is_enabled, enable_requested;
-- 
1.7.11.7