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>

diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index d7ad5139d17cefa543ae30652757b81ff48b407b..fe05ba27440ae2a502906e6c87d4d2530003e941 100644 (file)
--- 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;