73068ce3b5
Fix the start address calculation when overlay is partially off screen. fb->bits_per_pixel is not set for YUV formats, and is always zero, which led to the first component always starting at zero. Use drm_format_plane_cpp() instead. This also revealed a problem in that YUYV formats toggle the U/V data for odd pixel start address offsets. We try to rectify that by toggling the U/V swap, which for the most part works, but seemingly introduces a flicker for one scan frame of swapped U/V. However, these changes result in an overall improvement. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>