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FIXUP: "fbdev: Allow client to request a particular /dev/fbdevN node" #6893

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Merged
merged 1 commit into from
Jun 16, 2025
+1 −2
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FIXUP: "fbdev: Allow client to request a particular /dev/fbdevN node" #6893

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3 changes: 1 addition & 2 deletions drivers/video/fbdev/core/fbmem.c
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Original file line number Diff line number Diff line change
Expand Up @@ -446,12 +446,12 @@ static int do_register_framebuffer(struct fb_info *fb_info)
if (num_registered_fb == FB_MAX)
return -ENXIO;

i = fb_info->node;
if (!fb_info->custom_fb_num || fb_info->node >= FB_MAX || registered_fb[fb_info->node]) {
for (i = min_dynamic_fb ; i < FB_MAX; i++)
if (!registered_fb[i])
break;
}

if (!fb_info->modelist.prev || !fb_info->modelist.next)
INIT_LIST_HEAD(&fb_info->modelist);

Expand All @@ -460,7 +460,6 @@ static int do_register_framebuffer(struct fb_info *fb_info)
if (err < 0)
return err;

fb_info->node = i;
refcount_set(&fb_info->count, 1);
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Doesn't this deletion mean no one is ever setting fb_info->node?

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@6by9 6by9 Jun 11, 2025 •
edited
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If the caller has set custom_fb_num then it is also expected to have set fb_info->node to the desired node number.

We search if:

if (!fb_info->custom_fb_num || fb_info->node >= FB_MAX || registered_fb[fb_info->node]) {

ie caller hasn't requested to use the desired number, it's too high, or already registered.

dfc8f67 is the one user of this, and sets both info->node and info->custom_fb_num.

mutex_init(&fb_info->lock);
mutex_init(&fb_info->mm_lock);
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