Messages in this thread | | | Date | Mon, 02 Jul 2012 23:25:17 +0200 | From | Alexander Holler <> | Subject | Re: [PATCH] video/smscufx: fix line counting in fb_write |
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Hi Florian,
sorry for the late answer.
Am 13.05.2012 14:47, schrieb Florian Tobias Schandinat: > Hi Alexander, > > On 04/21/2012 11:26 AM, Alexander Holler wrote: >> Hello, >> >> as for the patch for udlfb, I forgot to mention that this is a candidate >> for all stable trees 3.2 and above. >> >> Btw., the address of the maintainer doesn't seem to be valid anymore. > > it is better to cc me on patches to the framebuffer subsystem for such > cases. I don't have much free time so it's rare that I come around to > dig in the mailing list. > >> >> Regards, >> >> Alexander >> >> Am 21.04.2012 00:11, schrieb Alexander Holler: >>> 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> >> >> Cc: stable@vger.kernel.org > > Patch looks good to me but can be made simpler. > >> >>> --- >>> drivers/video/smscufx.c | 2 +- >>> 1 files changed, 1 insertions(+), 1 deletions(-) >>> >>> diff --git a/drivers/video/smscufx.c b/drivers/video/smscufx.c >>> index ccbfef5..1e1e2d2 100644 >>> --- 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); > > the cast to int as well as the max is superfluous without the -1 as the > value can no longer be negative.
I had that impression too, but I wanted to change as less as possible, so I didn't had the need to check types and (their) sizes for possible overflows or such. I was lazy and just wanted to fix that one bug. ;)
> >>> int lines = min((u32)((result / info->fix.line_length) + 1), >>> (u32)info->var.yres); >>>
Regards,
Alexander
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