Hello Helge,
On Thu, Nov 09, 2023 at 10:55:41AM +0100, Helge Deller wrote:
> On 11/9/23 07:24, Uwe Kleine-König wrote:
> > Hello,
> >
> > On Wed, Nov 08, 2023 at 10:57:00PM +0100, Helge Deller wrote:
> > > On 11/8/23 22:52, Uwe Kleine-König wrote:
> > > > But info and so info->fix live longer than the probe function, don't
> > > > they?
> > >
> > > Yes, they do.
> > > But AFAICS info->fix contains a *copy* of the initial atmel_lcdfb_fix struct
> > > (and not a pointer to it). So that should be ok.
> >
> > If you say so that's good. I grepped a bit around and didn't find a
> > place where a copy is made. But that's probably me and I'll consider the
> > case closed.
>
> It's not directly obvious, but the copy happens in the line you pointed
> out previously.
>
> In include/linux/fb.h:
>
> struct fb_info {
> ...
> struct fb_var_screeninfo var; /* Current var */
> struct fb_fix_screeninfo fix; /* Current fix */
>
> so, "fb_info.fix" is a struct, and not a pointer.
>
> In drivers/video/fbdev/atmel_lcdfb.c:
> static int atmel_lcdfb_probe(struct platform_device *pdev)
> {
> ...
> info->fix = atmel_lcdfb_fix; // (line 1065)
>
> this becomes effectively a:
> memcpy(&info->fix, &atmel_lcdfb_fix, sizeof(struct fb_fix_screeninfo));
Ah right. Thanks for that hint. I didn't spot this and grepped for
memcpy and memdup.
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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