From 940f48d8897c4ca63cb9f0dfd5545d4fc3e60aea Mon Sep 17 00:00:00 2001 From: Dave Stevenson Date: Mon, 9 Oct 2023 16:32:45 +0100 Subject: [PATCH 394/697] 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 --- drivers/video/fbdev/core/fbmem.c | 19 ++++++++++++++----- include/linux/fb.h | 2 ++ 2 files changed, 16 insertions(+), 5 deletions(-) --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -31,6 +31,7 @@ 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 @@ -398,10 +399,12 @@ static int do_register_framebuffer(struc return -ENXIO; num_registered_fb++; - for (i = 0 ; i < FB_MAX; i++) - if (!registered_fb[i]) - break; - fb_info->node = i; + 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; + fb_info->node = i; + } refcount_set(&fb_info->count, 1); mutex_init(&fb_info->lock); mutex_init(&fb_info->mm_lock); @@ -436,7 +439,7 @@ static int do_register_framebuffer(struc fb_var_to_videomode(&mode, &fb_info->var); fb_add_videomode(&mode, &fb_info->modelist); - registered_fb[i] = fb_info; + registered_fb[fb_info->node] = fb_info; #ifdef CONFIG_GUMSTIX_AM200EPD { @@ -497,6 +500,12 @@ static void do_unregister_framebuffer(st 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 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -511,6 +511,7 @@ 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 @@ -600,6 +601,7 @@ extern ssize_t fb_sys_write(struct fb_in .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);