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

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Message-ID: <20190521150939.GQ21222@phenom.ffwll.local>
Date:   Tue, 21 May 2019 17:09:39 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     Thomas Zimmermann <tzimmermann@...e.de>
Cc:     Daniel Vetter <daniel.vetter@...ll.ch>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        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

On Mon, May 20, 2019 at 10:37:53AM +0200, Thomas Zimmermann wrote:
> 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.

I did screw this up for one event for the mode changes. But should be
fixed in the next series.

I also added a patch to simplify the backlight/lcd notifier, since it
doesn't need to filter events anymore after this series - the only events
left are the ones backlight cares about.

Cheers, Daniel

> 
> 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)
> 




-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch