drm/i915: Limit plane stride to below TILEOFF.x limit

Limit pre-skl plane stride to below 4k or 8k pixels (depending on
the platform). We do this in order guarantee that TILEOFF/OFFSET.x
does not get too big.

Currently this is not a problem as we align SURF to 4k, and so
TILEOFF/OFFSET only have to deal with a single tile's worth of
pixels. But for async flips we're going to have to bump SURF
alignment to 256k, and thus we can no longer guarantee
TILEOFF/OFFSET.x will stay within acceptable bounds. We can avoid
this by borrowing a trick from the skl+ code and limit the max
plane stride to whatever value we can fit into TILEOFF/OFFSET.x.

The slight downside is that we may end up doing GTT remapping in
a few more cases where previously we did not have to. But since
that will only happen with huge buffers I'm not really concerned
about it.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111163711.12913-3-ville.syrjala@linux.intel.com
Reviewed-by: Karthik B S <karthik.b.s@intel.com>

1 files changed, 27 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c
index 465fd18a77b0..993543334a1e 100644
--- a/drivers/gpu/drm/i915/display/intel_sprite.c
+++ b/drivers/gpu/drm/i915/display/intel_sprite.c
@@ -1851,7 +1851,26 @@ g4x_sprite_max_stride(struct intel_plane *plane,
 		      u32 pixel_format, u64 modifier,
 		      unsigned int rotation)
 {
-	return 16384;
+	const struct drm_format_info *info = drm_format_info(pixel_format);
+	int cpp = info->cpp[0];
+
+	/* Limit to 4k pixels to guarantee TILEOFF.x doesn't get too big. */
+	if (modifier == I915_FORMAT_MOD_X_TILED)
+		return min(4096 * cpp, 16 * 1024);
+	else
+		return 16 * 1024;
+}
+
+static unsigned int
+hsw_sprite_max_stride(struct intel_plane *plane,
+		      u32 pixel_format, u64 modifier,
+		      unsigned int rotation)
+{
+	const struct drm_format_info *info = drm_format_info(pixel_format);
+	int cpp = info->cpp[0];
+
+	/* Limit to 8k pixels to guarantee OFFSET.x doesn't get too big. */
+	return min(8192 * cpp, 16 * 1024);
 }
 
 static u32 g4x_sprite_ctl_crtc(const struct intel_crtc_state *crtc_state)
@@ -3408,11 +3427,11 @@ intel_sprite_plane_create(struct drm_i915_private *dev_priv,
 		return plane;
 
 	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
-		plane->max_stride = i9xx_plane_max_stride;
 		plane->update_plane = vlv_update_plane;
 		plane->disable_plane = vlv_disable_plane;
 		plane->get_hw_state = vlv_plane_get_hw_state;
 		plane->check_plane = vlv_sprite_check;
+		plane->max_stride = i965_plane_max_stride;
 		plane->min_cdclk = vlv_plane_min_cdclk;
 
 		if (IS_CHERRYVIEW(dev_priv) && pipe == PIPE_B) {
@@ -3426,16 +3445,18 @@ intel_sprite_plane_create(struct drm_i915_private *dev_priv,
 
 		plane_funcs = &vlv_sprite_funcs;
 	} else if (INTEL_GEN(dev_priv) >= 7) {
-		plane->max_stride = g4x_sprite_max_stride;
 		plane->update_plane = ivb_update_plane;
 		plane->disable_plane = ivb_disable_plane;
 		plane->get_hw_state = ivb_plane_get_hw_state;
 		plane->check_plane = g4x_sprite_check;
 
-		if (IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
+		if (IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv)) {
+			plane->max_stride = hsw_sprite_max_stride;
 			plane->min_cdclk = hsw_plane_min_cdclk;
-		else
+		} else {
+			plane->max_stride = g4x_sprite_max_stride;
 			plane->min_cdclk = ivb_sprite_min_cdclk;
+		}
 
 		formats = snb_plane_formats;
 		num_formats = ARRAY_SIZE(snb_plane_formats);
@@ -3443,11 +3464,11 @@ intel_sprite_plane_create(struct drm_i915_private *dev_priv,
 
 		plane_funcs = &snb_sprite_funcs;
 	} else {
-		plane->max_stride = g4x_sprite_max_stride;
 		plane->update_plane = g4x_update_plane;
 		plane->disable_plane = g4x_disable_plane;
 		plane->get_hw_state = g4x_plane_get_hw_state;
 		plane->check_plane = g4x_sprite_check;
+		plane->max_stride = g4x_sprite_max_stride;
 		plane->min_cdclk = g4x_sprite_min_cdclk;
 
 		modifiers = i9xx_plane_format_modifiers;