On 09/11/2023 at 10:55, 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));
so, the compiler copies the "__initconst" data over to the info->fix struct.
Helge, Uwe and Nathan,
Thanks a lot for making this move, patch and detailed explanation.
Best regards,
Nicolas
