# Re: \[PATCH\] fbdev/tcx.c fix mem\_map to correct smem\_start offset

- From: Helge Deller \<deller@gmx.de\>
- Date: 2025-12-02 18:43:37 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2025/12/13467360
- Thread: https://ratatoskr.run/linux-fbdev/2025/11/13467359/t.md

```text
On 11/20/25 14:24, René Rebe wrote:
> 403ae52ac047 ("sparc: fix drivers/video/tcx.c warning") changed the
> physbase initializing breaking the user-space mmap, e.g. for Xorg
> entirely.
>
> Fix fbdev mmap table so the sbus mmap helper work correctly, and
> not try to map vastly (physbase) offset memory.
>
> Fixes: 403ae52ac047 ("sparc: fix drivers/video/tcx.c warning")
> Signed-off-by: René Rebe <redacted>

Applied to fbdev.

Rene, shouldn't it be backported to all old Linux kernels?
Should I add a stable tag ?

Helge

 ---
>   drivers/video/fbdev/tcx.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/video/fbdev/tcx.c b/drivers/video/fbdev/tcx.c
> index f9a0085ad72b..ca9e84e8d860 100644
> --- a/drivers/video/fbdev/tcx.c
> +++ b/drivers/video/fbdev/tcx.c
> @@ -428,7 +428,7 @@ static int tcx_probe(struct platform_device *op)
>   			j = i;
>   			break;
>   		}
> -		par->mmap_map[i].poff = op->resource[j].start;
> +		par->mmap_map[i].poff = op->resource[j].start - info->fix.smem_start;
>   	}
>   
>   	info->fbops = &tcx_ops;

```