drm/i915: Actually respect DSPSURF alignment restrictions

Currently intel_gen4_compute_page_offset() simply picks the closest
page boundary below the linear offset. That however may not be suitably
aligned to satisfy any hardware specific restrictions. So let's make
sure the page boundary we choose is properly aligned.

Also to play it a bit safer lets split the remaining linear offset into
x and y values instead of just x. This should make no difference for
most platforms since we convert the x and y offsets back into a linear
offset before feeding them to the hardware. HSW+ are different however
and use x and y offsets even with linear buffers, so they might have
trouble if either the x or y get too big.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -2329,6 +2329,18 @@ intel_fill_fb_ggtt_view(struct i915_ggtt_view *view, struct drm_framebuffer *fb,
 	return 0;
 }
 
+static unsigned int intel_linear_alignment(struct drm_i915_private *dev_priv)
+{
+	if (INTEL_INFO(dev_priv)->gen >= 9)
+		return 256 * 1024;
+	else if (IS_BROADWATER(dev_priv) || IS_CRESTLINE(dev_priv))
+		return 128 * 1024;
+	else if (INTEL_INFO(dev_priv)->gen >= 4)
+		return 4 * 1024;
+	else
+		return 64 * 1024;
+}
+
 int
 intel_pin_and_fence_fb_obj(struct drm_plane *plane,
 			   struct drm_framebuffer *fb,
@@ -2346,14 +2358,7 @@ intel_pin_and_fence_fb_obj(struct drm_plane *plane,
 
 	switch (fb->modifier[0]) {
 	case DRM_FORMAT_MOD_NONE:
-		if (INTEL_INFO(dev)->gen >= 9)
-			alignment = 256 * 1024;
-		else if (IS_BROADWATER(dev) || IS_CRESTLINE(dev))
-			alignment = 128 * 1024;
-		else if (INTEL_INFO(dev)->gen >= 4)
-			alignment = 4 * 1024;
-		else
-			alignment = 64 * 1024;
+		alignment = intel_linear_alignment(dev_priv);
 		break;
 	case I915_FORMAT_MOD_X_TILED:
 		if (INTEL_INFO(dev)->gen >= 9)
@@ -2443,7 +2448,8 @@ static void intel_unpin_fb_obj(struct drm_framebuffer *fb,
 
 /* Computes the linear offset to the base tile and adjusts x, y. bytes per pixel
  * is assumed to be a power-of-two. */
-unsigned long intel_gen4_compute_page_offset(int *x, int *y,
+unsigned long intel_gen4_compute_page_offset(struct drm_i915_private *dev_priv,
+					     int *x, int *y,
 					     unsigned int tiling_mode,
 					     unsigned int cpp,
 					     unsigned int pitch)
@@ -2459,12 +2465,13 @@ unsigned long intel_gen4_compute_page_offset(int *x, int *y,
 
 		return tile_rows * pitch * 8 + tiles * 4096;
 	} else {
+		unsigned int alignment = intel_linear_alignment(dev_priv) - 1;
 		unsigned int offset;
 
 		offset = *y * pitch + *x * cpp;
-		*y = 0;
-		*x = (offset & 4095) / cpp;
-		return offset & -4096;
+		*y = (offset & alignment) / pitch;
+		*x = ((offset & alignment) - *y * pitch) / cpp;
+		return offset & ~alignment;
 	}
 }
 
@@ -2733,7 +2740,8 @@ static void i9xx_update_primary_plane(struct drm_crtc *crtc,
 
 	if (INTEL_INFO(dev)->gen >= 4) {
 		intel_crtc->dspaddr_offset =
-			intel_gen4_compute_page_offset(&x, &y, obj->tiling_mode,
+			intel_gen4_compute_page_offset(dev_priv,
+						       &x, &y, obj->tiling_mode,
 						       pixel_size,
 						       fb->pitches[0]);
 		linear_offset -= intel_crtc->dspaddr_offset;
@@ -2834,7 +2842,8 @@ static void ironlake_update_primary_plane(struct drm_crtc *crtc,
 
 	linear_offset = y * fb->pitches[0] + x * pixel_size;
 	intel_crtc->dspaddr_offset =
-		intel_gen4_compute_page_offset(&x, &y, obj->tiling_mode,
+		intel_gen4_compute_page_offset(dev_priv,
+					       &x, &y, obj->tiling_mode,
 					       pixel_size,
 					       fb->pitches[0]);
 	linear_offset -= intel_crtc->dspaddr_offset;

drivers/gpu/drm/i915/intel_drv.h

@@ -1113,7 +1113,8 @@ void assert_fdi_rx_pll(struct drm_i915_private *dev_priv,
 void assert_pipe(struct drm_i915_private *dev_priv, enum pipe pipe, bool state);
 #define assert_pipe_enabled(d, p) assert_pipe(d, p, true)
 #define assert_pipe_disabled(d, p) assert_pipe(d, p, false)
-unsigned long intel_gen4_compute_page_offset(int *x, int *y,
+unsigned long intel_gen4_compute_page_offset(struct drm_i915_private *dev_priv,
+					     int *x, int *y,
 					     unsigned int tiling_mode,
 					     unsigned int bpp,
 					     unsigned int pitch);

drivers/gpu/drm/i915/intel_sprite.c

@@ -411,7 +411,8 @@ vlv_update_plane(struct drm_plane *dplane, struct drm_crtc *crtc,
 	crtc_h--;
 
 	linear_offset = y * fb->pitches[0] + x * pixel_size;
-	sprsurf_offset = intel_gen4_compute_page_offset(&x, &y,
+	sprsurf_offset = intel_gen4_compute_page_offset(dev_priv,
+							&x, &y,
 							obj->tiling_mode,
 							pixel_size,
 							fb->pitches[0]);
@@ -546,7 +547,8 @@ ivb_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 
 	linear_offset = y * fb->pitches[0] + x * pixel_size;
 	sprsurf_offset =
-		intel_gen4_compute_page_offset(&x, &y, obj->tiling_mode,
+		intel_gen4_compute_page_offset(dev_priv,
+					       &x, &y, obj->tiling_mode,
 					       pixel_size, fb->pitches[0]);
 	linear_offset -= sprsurf_offset;
 
@@ -682,7 +684,8 @@ ilk_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 
 	linear_offset = y * fb->pitches[0] + x * pixel_size;
 	dvssurf_offset =
-		intel_gen4_compute_page_offset(&x, &y, obj->tiling_mode,
+		intel_gen4_compute_page_offset(dev_priv,
+					       &x, &y, obj->tiling_mode,
 					       pixel_size, fb->pitches[0]);
 	linear_offset -= dvssurf_offset;