Re: radeonfb broken

[James Simmons]

Thanks for the fix.


On Fri, 16 Apr 2004, Timothy Miller wrote:

> 
> Andrew Morton asked me to repost the patch for the Radeon FB off-by-one 
> bug.  I'll see about making a proper patch when I get home, but if you 
> want to fix it quicker, I'll just tell you what to change.
> 
> 
> In the druvers/video/radeonfb.c, there is a function called 
> fbcon_radeon_bmove.  In there, you'll see this code:
> 
> 	if (srcy < dsty) {
>                  srcy += height;
>                  dsty += height;
>          } else
>                  dp_cntl |= DST_Y_TOP_TO_BOTTOM;
> 
>          if (srcx < dstx) {
>                  srcx += width;
>                  dstx += width;
>          } else
>                  dp_cntl |= DST_X_LEFT_TO_RIGHT;
> 
> 
> Those adds need to be reduced by one.  The code should look like this:
> 
> 
> 	if (srcy < dsty) {
>                  srcy += height - 1;
>                  dsty += height - 1;
>          } else
>                  dp_cntl |= DST_Y_TOP_TO_BOTTOM;
> 
>          if (srcx < dstx) {
>                  srcx += width - 1;
>                  dstx += width - 1;
>          } else
>                  dp_cntl |= DST_X_LEFT_TO_RIGHT;
> 
> 
> 
> This bug is in the mainline kernel, and since I have direct experience 
> programming for the Radeon, I knew how to fix it, but I also noticed 
> that the Red Hat kernel "2.4.18-27.7.x" has the proper fix in it.
> 
> 
> Whenever I download a new 2.4 kernel for gentoo, I have to manually make 
> that fix.  I'm also disappointed that acceleration for Radeon has 
> disappeared completely from 2.6.
> 
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