drm/i915: push crtc->fb update into pipe_set_base

Passing in the old fb, having overwritten the current fb, leads to
some neatly convoluted code. It's much simpler if we defer the
crtc->fb update to the place that updates the hw, in pipe_set_base.
This way we also don't need to restore anything in case something
fails - we only update crtc->fb once things have succeeded.

The real reason for this change is that now we keep the old fb
assigned to crtc->fb, which allows us to finally move the crtc disable
case into the common low-level set_mode function in the next patch.

Also don't clobber crtc->x and crtc->y, we neatly pass these down the
callchain already. Unfortunately we can't do the same with crtc->mode,
because that one is being used in the mode_set callbacks.

v2: Don't restore the drm_crtc object any more on failed modesets,
since we've lose an fb reference otherwise. Also (and this is the
reason this has been found), this totally confused the modeset state
tracking, since it clobbers crtc->enabled. Issue reported by Paulo
Zanoni.

v3: Rip out the entire crtc saving into struct intel_set_config, not
just the restoring part.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5031e0c..9ce8c59 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2201,16 +2201,17 @@
 
 static int
 intel_pipe_set_base(struct drm_crtc *crtc, int x, int y,
-		    struct drm_framebuffer *old_fb)
+		    struct drm_framebuffer *fb)
 {
 	struct drm_device *dev = crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_master_private *master_priv;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	struct drm_framebuffer *old_fb;
 	int ret;
 
 	/* no fb bound */
-	if (!crtc->fb) {
+	if (!fb) {
 		DRM_ERROR("No FB bound\n");
 		return 0;
 	}
@@ -2224,7 +2225,7 @@
 
 	mutex_lock(&dev->struct_mutex);
 	ret = intel_pin_and_fence_fb_obj(dev,
-					 to_intel_framebuffer(crtc->fb)->obj,
+					 to_intel_framebuffer(fb)->obj,
 					 NULL);
 	if (ret != 0) {
 		mutex_unlock(&dev->struct_mutex);
@@ -2232,17 +2233,20 @@
 		return ret;
 	}
 
-	if (old_fb)
-		intel_finish_fb(old_fb);
+	if (crtc->fb)
+		intel_finish_fb(crtc->fb);
 
-	ret = dev_priv->display.update_plane(crtc, crtc->fb, x, y);
+	ret = dev_priv->display.update_plane(crtc, fb, x, y);
 	if (ret) {
-		intel_unpin_fb_obj(to_intel_framebuffer(crtc->fb)->obj);
+		intel_unpin_fb_obj(to_intel_framebuffer(fb)->obj);
 		mutex_unlock(&dev->struct_mutex);
 		DRM_ERROR("failed to update base address\n");
 		return ret;
 	}
 
+	old_fb = crtc->fb;
+	crtc->fb = fb;
+
 	if (old_fb) {
 		intel_wait_for_vblank(dev, intel_crtc->pipe);
 		intel_unpin_fb_obj(to_intel_framebuffer(old_fb)->obj);
@@ -3777,6 +3781,7 @@
  * true if they don't match).
  */
 static bool intel_choose_pipe_bpp_dither(struct drm_crtc *crtc,
+					 struct drm_framebuffer *fb,
 					 unsigned int *pipe_bpp,
 					 struct drm_display_mode *mode)
 {
@@ -3846,7 +3851,7 @@
 	 * also stays within the max display bpc discovered above.
 	 */
 
-	switch (crtc->fb->depth) {
+	switch (fb->depth) {
 	case 8:
 		bpc = 8; /* since we go through a colormap */
 		break;
@@ -4265,7 +4270,7 @@
 			      struct drm_display_mode *mode,
 			      struct drm_display_mode *adjusted_mode,
 			      int x, int y,
-			      struct drm_framebuffer *old_fb)
+			      struct drm_framebuffer *fb)
 {
 	struct drm_device *dev = crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -4455,7 +4460,7 @@
 	I915_WRITE(DSPCNTR(plane), dspcntr);
 	POSTING_READ(DSPCNTR(plane));
 
-	ret = intel_pipe_set_base(crtc, x, y, old_fb);
+	ret = intel_pipe_set_base(crtc, x, y, fb);
 
 	intel_update_watermarks(dev);
 
@@ -4613,7 +4618,7 @@
 				  struct drm_display_mode *mode,
 				  struct drm_display_mode *adjusted_mode,
 				  int x, int y,
-				  struct drm_framebuffer *old_fb)
+				  struct drm_framebuffer *fb)
 {
 	struct drm_device *dev = crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -4733,7 +4738,7 @@
 	/* determine panel color depth */
 	temp = I915_READ(PIPECONF(pipe));
 	temp &= ~PIPE_BPC_MASK;
-	dither = intel_choose_pipe_bpp_dither(crtc, &pipe_bpp, mode);
+	dither = intel_choose_pipe_bpp_dither(crtc, fb, &pipe_bpp, mode);
 	switch (pipe_bpp) {
 	case 18:
 		temp |= PIPE_6BPC;
@@ -5002,7 +5007,7 @@
 	I915_WRITE(DSPCNTR(plane), dspcntr);
 	POSTING_READ(DSPCNTR(plane));
 
-	ret = intel_pipe_set_base(crtc, x, y, old_fb);
+	ret = intel_pipe_set_base(crtc, x, y, fb);
 
 	intel_update_watermarks(dev);
 
@@ -5015,7 +5020,7 @@
 			       struct drm_display_mode *mode,
 			       struct drm_display_mode *adjusted_mode,
 			       int x, int y,
-			       struct drm_framebuffer *old_fb)
+			       struct drm_framebuffer *fb)
 {
 	struct drm_device *dev = crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -5026,7 +5031,7 @@
 	drm_vblank_pre_modeset(dev, pipe);
 
 	ret = dev_priv->display.crtc_mode_set(crtc, mode, adjusted_mode,
-					      x, y, old_fb);
+					      x, y, fb);
 	drm_vblank_post_modeset(dev, pipe);
 
 	return ret;
@@ -5718,7 +5723,7 @@
 	struct drm_encoder *encoder = &intel_encoder->base;
 	struct drm_crtc *crtc = NULL;
 	struct drm_device *dev = encoder->dev;
-	struct drm_framebuffer *old_fb;
+	struct drm_framebuffer *fb;
 	int i = -1;
 
 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
@@ -5779,8 +5784,6 @@
 	if (!mode)
 		mode = &load_detect_mode;
 
-	old_fb = crtc->fb;
-
 	/* We need a framebuffer large enough to accommodate all accesses
 	 * that the plane may generate whilst we perform load detection.
 	 * We can not rely on the fbcon either being present (we get called
@@ -5788,19 +5791,19 @@
 	 * not even exist) or that it is large enough to satisfy the
 	 * requested mode.
 	 */
-	crtc->fb = mode_fits_in_fbdev(dev, mode);
-	if (crtc->fb == NULL) {
+	fb = mode_fits_in_fbdev(dev, mode);
+	if (fb == NULL) {
 		DRM_DEBUG_KMS("creating tmp fb for load-detection\n");
-		crtc->fb = intel_framebuffer_create_for_mode(dev, mode, 24, 32);
-		old->release_fb = crtc->fb;
+		fb = intel_framebuffer_create_for_mode(dev, mode, 24, 32);
+		old->release_fb = fb;
 	} else
 		DRM_DEBUG_KMS("reusing fbdev for load-detection framebuffer\n");
-	if (IS_ERR(crtc->fb)) {
+	if (IS_ERR(fb)) {
 		DRM_DEBUG_KMS("failed to allocate framebuffer for load-detection\n");
 		goto fail;
 	}
 
-	if (!intel_set_mode(crtc, mode, 0, 0, old_fb)) {
+	if (!intel_set_mode(crtc, mode, 0, 0, fb)) {
 		DRM_DEBUG_KMS("failed to set mode on load-detect pipe\n");
 		if (old->release_fb)
 			old->release_fb->funcs->destroy(old->release_fb);
@@ -5814,7 +5817,6 @@
 fail:
 	connector->encoder = NULL;
 	encoder->crtc = NULL;
-	crtc->fb = old_fb;
 	return false;
 }
 
@@ -6666,13 +6668,12 @@
 
 bool intel_set_mode(struct drm_crtc *crtc,
 		    struct drm_display_mode *mode,
-		    int x, int y, struct drm_framebuffer *old_fb)
+		    int x, int y, struct drm_framebuffer *fb)
 {
 	struct drm_device *dev = crtc->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
 	struct drm_encoder_helper_funcs *encoder_funcs;
-	int saved_x, saved_y;
 	struct drm_encoder *encoder;
 	bool ret = true;
 
@@ -6686,15 +6687,11 @@
 
 	saved_hwmode = crtc->hwmode;
 	saved_mode = crtc->mode;
-	saved_x = crtc->x;
-	saved_y = crtc->y;
 
 	/* Update crtc values up front so the driver can rely on them for mode
 	 * setting.
 	 */
 	crtc->mode = *mode;
-	crtc->x = x;
-	crtc->y = y;
 
 	/* Pass our mode to the connectors and the CRTC to give them a chance to
 	 * adjust it according to limitations or connector properties, and also
@@ -6725,7 +6722,7 @@
 	/* Set up the DPLL and any encoders state that needs to adjust or depend
 	 * on the DPLL.
 	 */
-	ret = !intel_crtc_mode_set(crtc, mode, adjusted_mode, x, y, old_fb);
+	ret = !intel_crtc_mode_set(crtc, mode, adjusted_mode, x, y, fb);
 	if (!ret)
 	    goto done;
 
@@ -6741,6 +6738,9 @@
 		encoder_funcs->mode_set(encoder, mode, adjusted_mode);
 	}
 
+	crtc->x = x;
+	crtc->y = y;
+
 	/* Now enable the clocks, plane, pipe, and connectors that we set up. */
 	dev_priv->display.crtc_enable(crtc);
 
@@ -6759,8 +6759,6 @@
 	if (!ret) {
 		crtc->hwmode = saved_hwmode;
 		crtc->mode = saved_mode;
-		crtc->x = saved_x;
-		crtc->y = saved_y;
 	}
 
 	return ret;
@@ -6773,25 +6771,16 @@
 
 	kfree(config->save_connector_encoders);
 	kfree(config->save_encoder_crtcs);
-	kfree(config->save_crtcs);
 	kfree(config);
 }
 
 static int intel_set_config_save_state(struct drm_device *dev,
 				       struct intel_set_config *config)
 {
-	struct drm_crtc *crtc;
 	struct drm_encoder *encoder;
 	struct drm_connector *connector;
 	int count;
 
-	/* Allocate space for the backup of all (non-pointer) crtc, encoder and
-	 * connector data. */
-	config->save_crtcs = kcalloc(dev->mode_config.num_crtc,
-				     sizeof(struct drm_crtc), GFP_KERNEL);
-	if (!config->save_crtcs)
-		return -ENOMEM;
-
 	config->save_encoder_crtcs =
 		kcalloc(dev->mode_config.num_encoder,
 			sizeof(struct drm_crtc *), GFP_KERNEL);
@@ -6809,11 +6798,6 @@
 	 * restored, not the drivers personal bookkeeping.
 	 */
 	count = 0;
-	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
-		config->save_crtcs[count++] = *crtc;
-	}
-
-	count = 0;
 	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 		config->save_encoder_crtcs[count++] = encoder->crtc;
 	}
@@ -6829,17 +6813,11 @@
 static void intel_set_config_restore_state(struct drm_device *dev,
 					   struct intel_set_config *config)
 {
-	struct drm_crtc *crtc;
 	struct intel_encoder *encoder;
 	struct intel_connector *connector;
 	int count;
 
 	count = 0;
-	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
-		*crtc = config->save_crtcs[count++];
-	}
-
-	count = 0;
 	list_for_each_entry(encoder, &dev->mode_config.encoder_list, base.head) {
 		encoder->new_crtc =
 			to_intel_crtc(config->save_encoder_crtcs[count++]);
@@ -6994,7 +6972,6 @@
 static int intel_crtc_set_config(struct drm_mode_set *set)
 {
 	struct drm_device *dev;
-	struct drm_framebuffer *old_fb = NULL;
 	struct drm_mode_set save_set;
 	struct intel_set_config *config;
 	int ret;
@@ -7057,13 +7034,10 @@
 			DRM_DEBUG_KMS("attempting to set mode from"
 					" userspace\n");
 			drm_mode_debug_printmodeline(set->mode);
-			old_fb = set->crtc->fb;
-			set->crtc->fb = set->fb;
 			if (!intel_set_mode(set->crtc, set->mode,
-					    set->x, set->y, old_fb)) {
+					    set->x, set->y, set->fb)) {
 				DRM_ERROR("failed to set mode on [CRTC:%d]\n",
 					  set->crtc->base.id);
-				set->crtc->fb = old_fb;
 				ret = -EINVAL;
 				goto fail;
 			}
@@ -7076,18 +7050,8 @@
 		}
 		drm_helper_disable_unused_functions(dev);
 	} else if (config->fb_changed) {
-		set->crtc->x = set->x;
-		set->crtc->y = set->y;
-
-		old_fb = set->crtc->fb;
-		if (set->crtc->fb != set->fb)
-			set->crtc->fb = set->fb;
 		ret = intel_pipe_set_base(set->crtc,
-					  set->x, set->y, old_fb);
-		if (ret != 0) {
-			set->crtc->fb = old_fb;
-			goto fail;
-		}
+					  set->x, set->y, set->fb);
 	}
 
 	intel_set_config_free(config);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index ae807af..1aa0b9c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -442,7 +442,6 @@
 struct intel_set_config {
 	struct drm_encoder **save_connector_encoders;
 	struct drm_crtc **save_encoder_crtcs;
-	struct drm_crtc *save_crtcs;
 
 	bool fb_changed;
 	bool mode_changed;