fbdev: Allow client to request a particular /dev/fbN node

Add a flag custom_fb_num to denote that the client has
requested a specific fbdev node number via node.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
This commit is contained in:
Dave Stevenson
2023-10-09 16:32:45 +01:00
committed by Dom Cobley
parent 1494472cc1
commit c91c9f257d
2 changed files with 14 additions and 4 deletions

View File

@@ -33,6 +33,7 @@ struct class *fb_class;
DEFINE_MUTEX(registration_lock);
struct fb_info *registered_fb[FB_MAX] __read_mostly;
int num_registered_fb __read_mostly;
int min_dynamic_fb __read_mostly;
#define for_each_registered_fb(i) \
for (i = 0; i < FB_MAX; i++) \
if (!registered_fb[i]) {} else
@@ -445,9 +446,11 @@ static int do_register_framebuffer(struct fb_info *fb_info)
if (num_registered_fb == FB_MAX)
return -ENXIO;
for (i = 0 ; i < FB_MAX; i++)
if (!registered_fb[i])
break;
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 (i >= FB_MAX)
return -ENXIO;
@@ -460,7 +463,6 @@ 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);
mutex_init(&fb_info->lock);
mutex_init(&fb_info->mm_lock);
@@ -560,6 +562,12 @@ static void do_unregister_framebuffer(struct fb_info *fb_info)
put_fb_info(fb_info);
}
void fb_set_lowest_dynamic_fb(int min_fb_dev)
{
min_dynamic_fb = min_fb_dev;
}
EXPORT_SYMBOL(fb_set_lowest_dynamic_fb);
/**
* register_framebuffer - registers a frame buffer device
* @fb_info: frame buffer info structure

View File

@@ -516,6 +516,7 @@ struct fb_info {
bool skip_vt_switch; /* no VT switch on suspend/resume required */
bool skip_panic; /* Do not write to the fb after a panic */
bool custom_fb_num; /* Use value in node as the preferred node number */
};
/* This will go away
@@ -605,6 +606,7 @@ extern ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
.fb_imageblit = sys_imageblit
/* fbmem.c */
extern void fb_set_lowest_dynamic_fb(int min_fb_dev);
extern int register_framebuffer(struct fb_info *fb_info);
extern void unregister_framebuffer(struct fb_info *fb_info);
extern int devm_register_framebuffer(struct device *dev, struct fb_info *fb_info);