When configuring the frame memory window, the last column and row numbers are written to the column resp. page address registers. These numbers are thus one less than the actual window width resp. height.

While this is handled correctly in mipi_dbi_fb_dirty() since commit 03ceb1c8dfd1e293 ("drm/tinydrm: Fix setting of the column/page end addresses."), it is not in mipi_dbi_blank(). The latter still forgets to subtract one when calculating the most significant bytes of the column and row numbers, thus programming wrong values when the display width or height is a multiple of 256.

Fixes: 02dd95fe31693626 ("drm/tinydrm: Add MIPI DBI support") Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be --- drivers/gpu/drm/drm_mipi_dbi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c index e34058c721becd6b..16bff1be4b8ac622 100644 --- a/drivers/gpu/drm/drm_mipi_dbi.c +++ b/drivers/gpu/drm/drm_mipi_dbi.c @@ -367,9 +367,9 @@ static void mipi_dbi_blank(struct mipi_dbi_dev *dbidev) memset(dbidev->tx_buf, 0, len);

mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS, 0, 0, - (width >> 8) & 0xFF, (width - 1) & 0xFF); + ((width - 1) >> 8) & 0xFF, (width - 1) & 0xFF); mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS, 0, 0, - (height >> 8) & 0xFF, (height - 1) & 0xFF); + ((height - 1) >> 8) & 0xFF, (height - 1) & 0xFF); mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START, (u8 *)dbidev->tx_buf, len);