[Intel-gfx] [PATCH v2] drm/i915: Support variable cursor height on ivb+

[ville.syrjala at linux.intel.com]

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

IVB introduced the CUR_FBC_CTL register which allows reducing the cursor
height down to 8 lines from the otherwise square cursor dimensions.
Implement support for it.

Commandeer the otherwise unused intel_crtc->cursor_size to track the
current value of CUR_FBC_CTL so that we can avoid duplicating the
complicated device type checks in i9xx_update_cursor().

One caveat to note is that CUR_FBC_CTL can't be used with 180 degree
rotation, so when cursor rotation gets introduced some extra checks are
needed.

v2: Reverse the gen check to make it sane

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h      |  5 ++++-
 drivers/gpu/drm/i915/intel_display.c | 23 ++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 15c0eaa..572001b 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4169,7 +4169,9 @@ enum punit_power_well {
 #define   CURSOR_POS_SIGN       0x8000
 #define   CURSOR_X_SHIFT        0
 #define   CURSOR_Y_SHIFT        16
-#define CURSIZE			0x700a0
+#define CURSIZE			0x700a0 /* 845/865 */
+#define _CUR_FBC_CTL_A		0x700a0 /* ivb+ */
+#define   CUR_FBC_CTL_EN	(1 << 31)
 #define _CURBCNTR		0x700c0
 #define _CURBBASE		0x700c4
 #define _CURBPOS		0x700c8
@@ -4185,6 +4187,7 @@ enum punit_power_well {
 #define CURCNTR(pipe) _CURSOR2(pipe, _CURACNTR)
 #define CURBASE(pipe) _CURSOR2(pipe, _CURABASE)
 #define CURPOS(pipe) _CURSOR2(pipe, _CURAPOS)
+#define CUR_FBC_CTL(pipe) _CURSOR2(pipe, _CUR_FBC_CTL_A)
 
 #define CURSOR_A_OFFSET 0x70080
 #define CURSOR_B_OFFSET 0x700c0
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 7809177..092aba3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8208,6 +8208,7 @@ static void i9xx_update_cursor(struct drm_crtc *crtc, u32 base)
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int pipe = intel_crtc->pipe;
 	uint32_t cntl;
+	uint32_t fbc_ctl = 0;
 
 	cntl = 0;
 	if (base) {
@@ -8228,6 +8229,16 @@ static void i9xx_update_cursor(struct drm_crtc *crtc, u32 base)
 		}
 		cntl |= pipe << 28; /* Connect to correct pipe */
 	}
+
+	if (intel_crtc->cursor_height != intel_crtc->cursor_width)
+		fbc_ctl = CUR_FBC_CTL_EN | (intel_crtc->cursor_height - 1);
+
+	if (intel_crtc->cursor_size != fbc_ctl) {
+		I915_WRITE(CUR_FBC_CTL(pipe), fbc_ctl);
+		intel_crtc->cursor_size = fbc_ctl;
+		intel_crtc->cursor_cntl = 0;
+	}
+
 	if (IS_HASWELL(dev) || IS_BROADWELL(dev))
 		cntl |= CURSOR_PIPE_CSC_ENABLE;
 
@@ -8304,6 +8315,8 @@ static bool cursor_size_ok(struct drm_device *dev,
 	 * the width of their cursors, the height is arbitrary up to
 	 * the precision of the register. Everything else requires
 	 * square cursors, limited to a few power-of-two sizes.
+	 * ivb+ have CUR_FBC_CTL which allows reducing the cursor
+	 * height down to a minimum of 8 lines.
 	 */
 	if (IS_845G(dev) || IS_I865G(dev)) {
 		if ((width & 63) != 0)
@@ -8315,7 +8328,7 @@ static bool cursor_size_ok(struct drm_device *dev,
 		if (height > 1023)
 			return false;
 	} else {
-		switch (width | height) {
+		switch (width) {
 		case 256:
 		case 128:
 			if (IS_GEN2(dev))
@@ -8325,6 +8338,14 @@ static bool cursor_size_ok(struct drm_device *dev,
 		default:
 			return false;
 		}
+
+		if (INTEL_INFO(dev)->gen < 7 || IS_VALLEYVIEW(dev)) {
+			if (height != width)
+				return false;
+		} else {
+			if (height < 8 || height > width)
+				return false;
+		}
 	}
 
 	return true;
-- 
1.8.5.5