video/smscufx: fix line counting in fb_write

commit 2fe2d9f47cfe1a3e66e7d087368b3d7155b04c15 upstream.

Line 0 and 1 were both written to line 0 (on the display) and all subsequent
lines had an offset of -1. The result was that the last line on the display
was never overwritten by writes to /dev/fbN.

The origin of this bug seems to have been udlfb.

Signed-off-by: Alexander Holler <holler@ahsoftware.de>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/video/smscufx.c b/drivers/video/smscufx.c
index aaccffa..dd9533a 100644 (file)
--- a/drivers/video/smscufx.c
+++ b/drivers/video/smscufx.c
@@ -904,7 +904,7 @@ static ssize_t ufx_ops_write(struct fb_info *info, const char __user *buf,
        result = fb_sys_write(info, buf, count, ppos);
 
        if (result > 0) {
-               int start = max((int)(offset / info->fix.line_length) - 1, 0);
+               int start = max((int)(offset / info->fix.line_length), 0);
                int lines = min((u32)((result / info->fix.line_length) + 1),
                                (u32)info->var.yres);