drm/i915: Check overlay stride errata for i830 and i845

Apparently i830 and i845 cannot handle any stride that is not a multiple
of 256, unlike their brethren which do support 64 byte aligned strides.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index d7ad5139d17c..fe05ba27440a 100644
--- a/drivers/gpu/drm/i915/intel_overlay.c
+++ b/drivers/gpu/drm/i915/intel_overlay.c
@@ -958,7 +958,7 @@ static int check_overlay_src(struct drm_device *dev,
             || rec->src_width < N_HORIZ_Y_TAPS*4)
                 return -EINVAL;
 
-        /* check alingment constrains */
+        /* check alignment constraints */
         switch (rec->flags & I915_OVERLAY_TYPE_MASK) {
                 case I915_OVERLAY_RGB:
                         /* not implemented */
@@ -990,7 +990,10 @@ static int check_overlay_src(struct drm_device *dev,
                 return -EINVAL;
 
         /* stride checking */
-        stride_mask = 63;
+        if (IS_I830(dev) || IS_845G(dev))
+                stride_mask = 255;
+        else
+                stride_mask = 63;
 
         if (rec->stride_Y & stride_mask || rec->stride_UV & stride_mask)
                 return -EINVAL;