drm/i915: Always apply cursor width changes

It is possible for userspace to create a big object large enough for a
256x256, and then switch over to using it as a 64x64 cursor. This
requires the cursor update routines to check for a change in width on
every update, rather than just when the cursor is originally enabled.

This also fixes an issue with 845g/865g which cannot change the base
address of the cursor whilst it is active.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[Antti:rebased, adjusted macro names and moved some lines, no functional
changes]
Reviewed-by: Antti Koskipaa <antti.koskipaa@linux.intel.com>
Tested-by: Antti Koskipaa <antti.koskipaa@linux.intel.com>
Cc: stable@vger.kernel.org
Testcase: igt/kms_cursor_crc/cursor-size-change
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2353,7 +2353,7 @@ static int i915_display_info(struct seq_file *m, void *unused)
 
 			active = cursor_position(dev, crtc->pipe, &x, &y);
 			seq_printf(m, "\tcursor visible? %s, position (%d, %d), addr 0x%08x, active? %s\n",
-				   yesno(crtc->cursor_visible),
+				   yesno(crtc->cursor_base),
 				   x, y, crtc->cursor_addr,
 				   yesno(active));
 		}

drivers/gpu/drm/i915/intel_display.c

@@ -7866,29 +7866,33 @@ static void i845_update_cursor(struct drm_crtc *crtc, u32 base)
 	struct drm_device *dev = crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	bool visible = base != 0;
-	u32 cntl;
+	uint32_t cntl;
 
-	if (intel_crtc->cursor_visible == visible)
-		return;
-
-	cntl = I915_READ(_CURACNTR);
-	if (visible) {
+	if (base != intel_crtc->cursor_base) {
 		/* On these chipsets we can only modify the base whilst
 		 * the cursor is disabled.
 		 */
+		if (intel_crtc->cursor_cntl) {
+			I915_WRITE(_CURACNTR, 0);
+			POSTING_READ(_CURACNTR);
+			intel_crtc->cursor_cntl = 0;
+		}
+
 		I915_WRITE(_CURABASE, base);
+		POSTING_READ(_CURABASE);
+	}
 
-		cntl &= ~(CURSOR_FORMAT_MASK);
 	/* XXX width must be 64, stride 256 => 0x00 << 28 */
-		cntl |= CURSOR_ENABLE |
+	cntl = 0;
+	if (base)
+		cntl = (CURSOR_ENABLE |
 			CURSOR_GAMMA_ENABLE |
-			CURSOR_FORMAT_ARGB;
-	} else
-		cntl &= ~(CURSOR_ENABLE | CURSOR_GAMMA_ENABLE);
+			CURSOR_FORMAT_ARGB);
+	if (intel_crtc->cursor_cntl != cntl) {
 		I915_WRITE(_CURACNTR, cntl);
-
-	intel_crtc->cursor_visible = visible;
+		POSTING_READ(_CURACNTR);
+		intel_crtc->cursor_cntl = cntl;
+	}
 }
 
 static void i9xx_update_cursor(struct drm_crtc *crtc, u32 base)
@@ -7897,16 +7901,12 @@ static void i9xx_update_cursor(struct drm_crtc *crtc, u32 base)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int pipe = intel_crtc->pipe;
-	bool visible = base != 0;
+	uint32_t cntl;
 
-	if (intel_crtc->cursor_visible != visible) {
-		int16_t width = intel_crtc->cursor_width;
-		uint32_t cntl = I915_READ(CURCNTR(pipe));
+	cntl = 0;
 	if (base) {
-			cntl &= ~(CURSOR_MODE | MCURSOR_PIPE_SELECT);
-			cntl |= MCURSOR_GAMMA_ENABLE;
-
-			switch (width) {
+		cntl = MCURSOR_GAMMA_ENABLE;
+		switch (intel_crtc->cursor_width) {
 			case 64:
 				cntl |= CURSOR_MODE_64_ARGB_AX;
 				break;
@@ -7921,16 +7921,14 @@ static void i9xx_update_cursor(struct drm_crtc *crtc, u32 base)
 				return;
 		}
 		cntl |= pipe << 28; /* Connect to correct pipe */
-		} else {
-			cntl &= ~(CURSOR_MODE | MCURSOR_GAMMA_ENABLE);
-			cntl |= CURSOR_MODE_DISABLE;
 	}
+	if (intel_crtc->cursor_cntl != cntl) {
 		I915_WRITE(CURCNTR(pipe), cntl);
-
-		intel_crtc->cursor_visible = visible;
+		POSTING_READ(CURCNTR(pipe));
+		intel_crtc->cursor_cntl = cntl;
 	}
+
 	/* and commit changes on next vblank */
-	POSTING_READ(CURCNTR(pipe));
 	I915_WRITE(CURBASE(pipe), base);
 	POSTING_READ(CURBASE(pipe));
 }
@@ -7941,15 +7939,12 @@ static void ivb_update_cursor(struct drm_crtc *crtc, u32 base)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int pipe = intel_crtc->pipe;
-	bool visible = base != 0;
+	uint32_t cntl;
 
-	if (intel_crtc->cursor_visible != visible) {
-		int16_t width = intel_crtc->cursor_width;
-		uint32_t cntl = I915_READ(CURCNTR(pipe));
+	cntl = 0;
 	if (base) {
-			cntl &= ~CURSOR_MODE;
-			cntl |= MCURSOR_GAMMA_ENABLE;
-			switch (width) {
+		cntl = MCURSOR_GAMMA_ENABLE;
+		switch (intel_crtc->cursor_width) {
 			case 64:
 				cntl |= CURSOR_MODE_64_ARGB_AX;
 				break;
@@ -7963,20 +7958,17 @@ static void ivb_update_cursor(struct drm_crtc *crtc, u32 base)
 				WARN_ON(1);
 				return;
 		}
-		} else {
-			cntl &= ~(CURSOR_MODE | MCURSOR_GAMMA_ENABLE);
-			cntl |= CURSOR_MODE_DISABLE;
 	}
-		if (IS_HASWELL(dev) || IS_BROADWELL(dev)) {
+	if (IS_HASWELL(dev) || IS_BROADWELL(dev))
 		cntl |= CURSOR_PIPE_CSC_ENABLE;
-			cntl &= ~CURSOR_TRICKLE_FEED_DISABLE;
-		}
-		I915_WRITE(CURCNTR(pipe), cntl);
 
-		intel_crtc->cursor_visible = visible;
+	if (intel_crtc->cursor_cntl != cntl) {
+		I915_WRITE(CURCNTR(pipe), cntl);
+		POSTING_READ(CURCNTR(pipe));
+		intel_crtc->cursor_cntl = cntl;
 	}
+
 	/* and commit changes on next vblank */
-	POSTING_READ(CURCNTR(pipe));
 	I915_WRITE(CURBASE(pipe), base);
 	POSTING_READ(CURBASE(pipe));
 }
@@ -7992,7 +7984,6 @@ static void intel_crtc_update_cursor(struct drm_crtc *crtc,
 	int x = intel_crtc->cursor_x;
 	int y = intel_crtc->cursor_y;
 	u32 base = 0, pos = 0;
-	bool visible;
 
 	if (on)
 		base = intel_crtc->cursor_addr;
@@ -8021,8 +8012,7 @@ static void intel_crtc_update_cursor(struct drm_crtc *crtc,
 	}
 	pos |= y << CURSOR_Y_SHIFT;
 
-	visible = base != 0;
-	if (!visible && !intel_crtc->cursor_visible)
+	if (base == 0 && intel_crtc->cursor_base == 0)
 		return;
 
 	I915_WRITE(CURPOS(pipe), pos);
@@ -8033,6 +8023,7 @@ static void intel_crtc_update_cursor(struct drm_crtc *crtc,
 		i845_update_cursor(crtc, base);
 	else
 		i9xx_update_cursor(crtc, base);
+	intel_crtc->cursor_base = base;
 }
 
 static int intel_crtc_cursor_set(struct drm_crtc *crtc,
@@ -10993,6 +10984,9 @@ static void intel_crtc_init(struct drm_device *dev, int pipe)
 		intel_crtc->plane = !pipe;
 	}
 
+	intel_crtc->cursor_base = ~0;
+	intel_crtc->cursor_cntl = ~0;
+
 	init_waitqueue_head(&intel_crtc->vbl_wait);
 
 	BUG_ON(pipe >= ARRAY_SIZE(dev_priv->plane_to_crtc_mapping) ||

drivers/gpu/drm/i915/intel_drv.h

@@ -386,7 +386,8 @@ struct intel_crtc {
 	uint32_t cursor_addr;
 	int16_t cursor_x, cursor_y;
 	int16_t cursor_width, cursor_height;
-	bool cursor_visible;
+	uint32_t cursor_cntl;
+	uint32_t cursor_base;
 
 	struct intel_plane_config plane_config;
 	struct intel_crtc_config config;