linux-kernel - Re: [PATCH 10/33] fbcon: call fbcon_fb

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Message-ID: <8aecc0d8-83a3-8144-a266-441a5c1d5db5@suse.de>
Date:   Mon, 20 May 2019 10:37:53 +0200
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     Daniel Vetter <daniel.vetter@...ll.ch>,
        DRI Development <dri-devel@...ts.freedesktop.org>
Cc:     Intel Graphics Development <intel-gfx@...ts.freedesktop.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Noralf Trønnes <noralf@...nnes.org>,
        Yisheng Xie <ysxie@...mail.com>, Peter Rosin <peda@...ntia.se>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Mikulas Patocka <mpatocka@...hat.com>,
        linux-fbdev@...r.kernel.org
Subject: Re: [PATCH 10/33] fbcon: call fbcon_fb_(un)registered directly

Hi

Am 20.05.19 um 10:33 schrieb Thomas Zimmermann:
> Hi
> 
> Am 20.05.19 um 10:21 schrieb Daniel Vetter:
> ...
>> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
>> index fc3d34a8ea5b..ae2db31eeba7 100644
>> --- a/drivers/video/fbdev/core/fbmem.c
>> +++ b/drivers/video/fbdev/core/fbmem.c
>> @@ -1660,7 +1660,6 @@ MODULE_PARM_DESC(lockless_register_fb,
>>  static int do_register_framebuffer(struct fb_info *fb_info)
>>  {
>>  	int i, ret;
>> -	struct fb_event event;
>>  	struct fb_videomode mode;
>>  
>>  	if (fb_check_foreignness(fb_info))
>> @@ -1723,7 +1722,6 @@ static int do_register_framebuffer(struct fb_info *fb_info)
>>  	fb_add_videomode(&mode, &fb_info->modelist);
>>  	registered_fb[i] = fb_info;
>>  
>> -	event.info = fb_info;
>>  	if (!lockless_register_fb)
>>  		console_lock();
>>  	else
>> @@ -1732,9 +1730,8 @@ static int do_register_framebuffer(struct fb_info *fb_info)
>>  		ret = -ENODEV;
>>  		goto unlock_console;
>>  	}
>> -	ret = 0;
>>  
>> -	fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
>> +	ret = fbcon_fb_registered(fb_info);
> 
> What about backlight drivers? [1] Apparently these also use the
> notifiers. [2] From my understanding, backlight drivers would stop
> working with this change.

I just saw that backlight drivers only care about blanking and
unblanking. Never mind then.

Best regards
Thomas

> 
> Best regards
> Thomas
> 
> [1]
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/video/backlight
> [2]
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/video/backlight/backlight.c#n40
> 
>>  	unlock_fb_info(fb_info);
>>  unlock_console:
>>  	if (!lockless_register_fb)
>> @@ -1771,7 +1768,6 @@ static int __unlink_framebuffer(struct fb_info *fb_info);
>>  
>>  static int do_unregister_framebuffer(struct fb_info *fb_info)
>>  {
>> -	struct fb_event event;
>>  	int ret;
>>  
>>  	ret = unbind_console(fb_info);
>> @@ -1789,9 +1785,8 @@ static int do_unregister_framebuffer(struct fb_info *fb_info)
>>  	registered_fb[fb_info->node] = NULL;
>>  	num_registered_fb--;
>>  	fb_cleanup_device(fb_info);
>> -	event.info = fb_info;
>>  	console_lock();
>> -	fb_notifier_call_chain(FB_EVENT_FB_UNREGISTERED, &event);
>> +	fbcon_fb_unregistered(fb_info);
>>  	console_unlock();
>>  
>>  	/* this may free fb info */
>> diff --git a/include/linux/fb.h b/include/linux/fb.h
>> index f52ef0ad6781..701abaf79c87 100644
>> --- a/include/linux/fb.h
>> +++ b/include/linux/fb.h
>> @@ -136,10 +136,6 @@ struct fb_cursor_user {
>>  #define FB_EVENT_RESUME			0x03
>>  /*      An entry from the modelist was removed */
>>  #define FB_EVENT_MODE_DELETE            0x04
>> -/*      A driver registered itself */
>> -#define FB_EVENT_FB_REGISTERED          0x05
>> -/*      A driver unregistered itself */
>> -#define FB_EVENT_FB_UNREGISTERED        0x06
>>  /*      CONSOLE-SPECIFIC: get console to framebuffer mapping */
>>  #define FB_EVENT_GET_CONSOLE_MAP        0x07
>>  /*      CONSOLE-SPECIFIC: set console to framebuffer mapping */
>> diff --git a/include/linux/fbcon.h b/include/linux/fbcon.h
>> index f68a7db14165..94a71e9e1257 100644
>> --- a/include/linux/fbcon.h
>> +++ b/include/linux/fbcon.h
>> @@ -4,9 +4,13 @@
>>  #ifdef CONFIG_FRAMEBUFFER_CONSOLE
>>  void __init fb_console_init(void);
>>  void __exit fb_console_exit(void);
>> +int fbcon_fb_registered(struct fb_info *info);
>> +void fbcon_fb_unregistered(struct fb_info *info);
>>  #else
>>  static inline void fb_console_init(void) {}
>>  static inline void fb_console_exit(void) {}
>> +static inline int fbcon_fb_registered(struct fb_info *info) { return 0; }
>> +static inline void fbcon_fb_unregistered(struct fb_info *info) {}
>>  #endif
>>  
>>  #endif /* _LINUX_FBCON_H */
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)



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