[PATCH 3/3] drm/tinydrm: Fix setting of the column/page end addresses.

From: Eric Anholt
Date: Wed Oct 24 2018 - 14:43:19 EST


If the clipped dirty region's x/y happened to align to 256, we would
have set the top 8 bits wrong. Noticed by inspection, not by
reproducing a bug.

Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
---
drivers/gpu/drm/tinydrm/mipi-dbi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
index cb3441e51d5f..1bb870021f6e 100644
--- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
+++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
@@ -240,10 +240,10 @@ static int mipi_dbi_fb_dirty(struct drm_framebuffer *fb,

mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
(clip.x1 >> 8) & 0xFF, clip.x1 & 0xFF,
- (clip.x2 >> 8) & 0xFF, (clip.x2 - 1) & 0xFF);
+ ((clip.x2 - 1) >> 8) & 0xFF, (clip.x2 - 1) & 0xFF);
mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,
(clip.y1 >> 8) & 0xFF, clip.y1 & 0xFF,
- (clip.y2 >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);
+ ((clip.y2 - 1) >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);

ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START, tr,
(clip.x2 - clip.x1) * (clip.y2 - clip.y1) * 2);
--
2.19.1