diff mbox series

[21/21] fbdev: Make registered_fb[] private to fbmem.c

Message ID 20220131210552.482606-22-daniel.vetter@ffwll.ch (mailing list archive)
State New, archived
Headers show
Series some fbcon patches, mostly locking | expand

Commit Message

Daniel Vetter Jan. 31, 2022, 9:05 p.m. UTC 
Well except when the olpc dcon fbdev driver is enabled, that thing
digs around in there in rather unfixable ways.

Cc oldc_dcon maintainers as fyi.

Cc: Jens Frederich <jfrederich@gmail.com>
Cc: Jon Nettleton <jon.nettleton@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-staging@lists.linux.dev
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Cc: linux-fbdev@vger.kernel.org
Cc: Zheyu Ma <zheyuma97@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
---
 drivers/video/fbdev/core/fbmem.c | 8 ++++++--
 include/linux/fb.h               | 7 +++----
 2 files changed, 9 insertions(+), 6 deletions(-)

Comments

kernel test robot Feb. 1, 2022, 8:13 a.m. UTC | #1 
Hi Daniel,

I love your patch! Yet something to improve:

[auto build test ERROR on tegra-drm/drm/tegra/for-next]
[also build test ERROR on drm/drm-next linus/master v5.17-rc2 next-20220131]
[cannot apply to airlied/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Daniel-Vetter/some-fbcon-patches-mostly-locking/20220201-050907
base:   git://anongit.freedesktop.org/tegra/linux.git drm/tegra/for-next
config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20220201/202202011603.vczWPod7-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/245da5ab93b17c0cf1521713d5bde655a72efb65
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Daniel-Vetter/some-fbcon-patches-mostly-locking/20220201-050907
        git checkout 245da5ab93b17c0cf1521713d5bde655a72efb65
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/staging/olpc_dcon/olpc_dcon.c: In function 'dcon_probe':
>> drivers/staging/olpc_dcon/olpc_dcon.c:605:6: error: 'num_registered_fb' undeclared (first use in this function); did you mean 'WB_registered'?
     605 |  if (num_registered_fb < 1) {
         |      ^~~~~~~~~~~~~~~~~
         |      WB_registered
   drivers/staging/olpc_dcon/olpc_dcon.c:605:6: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/staging/olpc_dcon/olpc_dcon.c:610:17: error: 'registered_fb' undeclared (first use in this function)
     610 |  dcon->fbinfo = registered_fb[0];
         |                 ^~~~~~~~~~~~~


vim +605 drivers/staging/olpc_dcon/olpc_dcon.c

53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  584  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  585  static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  586  {
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  587  	struct dcon_priv *dcon;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  588  	int rc, i, j;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  589  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  590  	if (!pdata)
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  591  		return -ENXIO;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  592  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  593  	dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  594  	if (!dcon)
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  595  		return -ENOMEM;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  596  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  597  	dcon->client = client;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  598  	init_waitqueue_head(&dcon->waitq);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  599  	INIT_WORK(&dcon->switch_source, dcon_source_switch);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  600  	dcon->reboot_nb.notifier_call = dcon_reboot_notify;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  601  	dcon->reboot_nb.priority = -1;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  602  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  603  	i2c_set_clientdata(client, dcon);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  604  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04 @605  	if (num_registered_fb < 1) {
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  606  		dev_err(&client->dev, "DCON driver requires a registered fb\n");
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  607  		rc = -EIO;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  608  		goto einit;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  609  	}
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04 @610  	dcon->fbinfo = registered_fb[0];
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  611  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  612  	rc = dcon_hw_init(dcon, 1);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  613  	if (rc)
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  614  		goto einit;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  615  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  616  	/* Add the DCON device */
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  617  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  618  	dcon_device = platform_device_alloc("dcon", -1);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  619  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  620  	if (!dcon_device) {
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  621  		pr_err("Unable to create the DCON device\n");
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  622  		rc = -ENOMEM;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  623  		goto eirq;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  624  	}
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  625  	rc = platform_device_add(dcon_device);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  626  	platform_set_drvdata(dcon_device, dcon);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  627  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  628  	if (rc) {
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  629  		pr_err("Unable to add the DCON device\n");
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  630  		goto edev;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  631  	}
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  632  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  633  	for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  634  		rc = device_create_file(&dcon_device->dev,
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  635  					&dcon_device_files[i]);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  636  		if (rc) {
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  637  			dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  638  			goto ecreate;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  639  		}
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  640  	}
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  641  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  642  	dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  643  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  644  	/* Add the backlight device for the DCON */
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  645  	dcon_bl_props.brightness = dcon->bl_val;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  646  	dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
848d9eabcaebf21 Zebulon McCorkle   2017-11-21  647  						 dcon, &dcon_bl_ops,
848d9eabcaebf21 Zebulon McCorkle   2017-11-21  648  						 &dcon_bl_props);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  649  	if (IS_ERR(dcon->bl_dev)) {
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  650  		dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  651  			PTR_ERR(dcon->bl_dev));
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  652  		dcon->bl_dev = NULL;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  653  	}
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  654  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  655  	register_reboot_notifier(&dcon->reboot_nb);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  656  	atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  657  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  658  	return 0;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  659  
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  660   ecreate:
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  661  	for (j = 0; j < i; j++)
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  662  		device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
4996b4610767064 Jing Xiangfeng     2020-11-20  663  	platform_device_del(dcon_device);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  664   edev:
4996b4610767064 Jing Xiangfeng     2020-11-20  665  	platform_device_put(dcon_device);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  666  	dcon_device = NULL;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  667   eirq:
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  668  	free_irq(DCON_IRQ, dcon);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  669   einit:
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  670  	kfree(dcon);
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  671  	return rc;
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  672  }
53c43c5ca13328a Greg Kroah-Hartman 2016-04-04  673  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Geert Uytterhoeven Feb. 4, 2022, 8:30 a.m. UTC | #2 
Hi Daniel,

Thanks for your patch!

On Tue, Feb 1, 2022 at 9:50 PM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> Well except when the olpc dcon fbdev driver is enabled, that thing
> digs around in there in rather unfixable ways.

Can't the actual frame buffer driver (which one?) used on olpc export
a pointer to its fb_info?

> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -48,10 +48,14 @@
>  static DEFINE_MUTEX(registration_lock);
>
>  struct fb_info *registered_fb[FB_MAX] __read_mostly;
> -EXPORT_SYMBOL(registered_fb);
> -
>  int num_registered_fb __read_mostly;
> +#if IS_ENABLED(CONFIG_OLPC_DCON)

CONFIG_FB_OLPC_DCON (everywhere), cfr. the build failure reported
by the robot.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Daniel Vetter Feb. 8, 2022, 2:04 p.m. UTC | #3 
On Fri, Feb 04, 2022 at 09:30:56AM +0100, Geert Uytterhoeven wrote:
> Hi Daniel,
> 
> Thanks for your patch!
> 
> On Tue, Feb 1, 2022 at 9:50 PM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> > Well except when the olpc dcon fbdev driver is enabled, that thing
> > digs around in there in rather unfixable ways.
> 
> Can't the actual frame buffer driver (which one?) used on olpc export
> a pointer to its fb_info?

Yeah that might be the right thing to do, I'll add that as a stagin TODO
in the next iteration.

> 
> > --- a/drivers/video/fbdev/core/fbmem.c
> > +++ b/drivers/video/fbdev/core/fbmem.c
> > @@ -48,10 +48,14 @@
> >  static DEFINE_MUTEX(registration_lock);
> >
> >  struct fb_info *registered_fb[FB_MAX] __read_mostly;
> > -EXPORT_SYMBOL(registered_fb);
> > -
> >  int num_registered_fb __read_mostly;
> > +#if IS_ENABLED(CONFIG_OLPC_DCON)
> 
> CONFIG_FB_OLPC_DCON (everywhere), cfr. the build failure reported
> by the robot.

Yeah realized that too and fixed it locally.

Cheers, Daniel

> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
Sam Ravnborg Feb. 8, 2022, 7 p.m. UTC | #4 
Hi Daniel,

On Mon, Jan 31, 2022 at 10:05:52PM +0100, Daniel Vetter wrote:
> Well except when the olpc dcon fbdev driver is enabled, that thing
> digs around in there in rather unfixable ways.
> 
> Cc oldc_dcon maintainers as fyi.
> 
> Cc: Jens Frederich <jfrederich@gmail.com>
> Cc: Jon Nettleton <jon.nettleton@gmail.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-staging@lists.linux.dev
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Helge Deller <deller@gmx.de>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
> Cc: Zhen Lei <thunder.leizhen@huawei.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Cc: linux-fbdev@vger.kernel.org
> Cc: Zheyu Ma <zheyuma97@gmail.com>
> Cc: Guenter Roeck <linux@roeck-us.net>

with the build thingy fixed:
Acked-by: Sam Ravnborg <sam@ravnborg.org>

I do wonder if there is a more clean way to trigger a blank
in the main fbdev driver from the olpc driver.

The current hack is not nice and it would be good to see it gone.

	Sam

> ---
>  drivers/video/fbdev/core/fbmem.c | 8 ++++++--
>  include/linux/fb.h               | 7 +++----
>  2 files changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> index 904ef1250677..dad6572942fa 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -48,10 +48,14 @@
>  static DEFINE_MUTEX(registration_lock);
>  
>  struct fb_info *registered_fb[FB_MAX] __read_mostly;
> -EXPORT_SYMBOL(registered_fb);
> -
>  int num_registered_fb __read_mostly;
> +#if IS_ENABLED(CONFIG_OLPC_DCON)
> +EXPORT_SYMBOL(registered_fb);
>  EXPORT_SYMBOL(num_registered_fb);
> +#endif
> +#define for_each_registered_fb(i)		\
> +	for (i = 0; i < FB_MAX; i++)		\
> +		if (!registered_fb[i]) {} else
>  
>  bool fb_center_logo __read_mostly;
>  
> diff --git a/include/linux/fb.h b/include/linux/fb.h
> index a8a00d2ba1f3..e236817502c2 100644
> --- a/include/linux/fb.h
> +++ b/include/linux/fb.h
> @@ -622,16 +622,15 @@ extern int fb_get_color_depth(struct fb_var_screeninfo *var,
>  extern int fb_get_options(const char *name, char **option);
>  extern int fb_new_modelist(struct fb_info *info);
>  
> +#if IS_ENABLED(CONFIG_OLPC_DCON)
>  extern struct fb_info *registered_fb[FB_MAX];
> +
>  extern int num_registered_fb;
> +#endif
>  extern bool fb_center_logo;
>  extern int fb_logo_count;
>  extern struct class *fb_class;
>  
> -#define for_each_registered_fb(i)		\
> -	for (i = 0; i < FB_MAX; i++)		\
> -		if (!registered_fb[i]) {} else
> -
>  static inline void lock_fb_info(struct fb_info *info)
>  {
>  	mutex_lock(&info->lock);
> -- 
> 2.33.0
Daniel Vetter Feb. 8, 2022, 8:56 p.m. UTC | #5 
On Tue, Feb 08, 2022 at 08:00:38PM +0100, Sam Ravnborg wrote:
> Hi Daniel,
> 
> On Mon, Jan 31, 2022 at 10:05:52PM +0100, Daniel Vetter wrote:
> > Well except when the olpc dcon fbdev driver is enabled, that thing
> > digs around in there in rather unfixable ways.
> > 
> > Cc oldc_dcon maintainers as fyi.
> > 
> > Cc: Jens Frederich <jfrederich@gmail.com>
> > Cc: Jon Nettleton <jon.nettleton@gmail.com>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: linux-staging@lists.linux.dev
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Cc: Helge Deller <deller@gmx.de>
> > Cc: Matthew Wilcox <willy@infradead.org>
> > Cc: Sam Ravnborg <sam@ravnborg.org>
> > Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
> > Cc: Zhen Lei <thunder.leizhen@huawei.com>
> > Cc: Alex Deucher <alexander.deucher@amd.com>
> > Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> > Cc: linux-fbdev@vger.kernel.org
> > Cc: Zheyu Ma <zheyuma97@gmail.com>
> > Cc: Guenter Roeck <linux@roeck-us.net>
> 
> with the build thingy fixed:
> Acked-by: Sam Ravnborg <sam@ravnborg.org>
> 
> I do wonder if there is a more clean way to trigger a blank
> in the main fbdev driver from the olpc driver.
> 
> The current hack is not nice and it would be good to see it gone.

Yeah this is just badly engineered. In drm we'd do this with the self
refresh helpers, which pretty much give you this exact functionality, but
in the helpers, while not randomly breaking actual visible behaviour of
the display driver.

Well ok the illusion is not perfect, since if the display is suspended the
next page flip will take a tad longer. But that's it.

I'll also add this to the TODO.
-Daniel

> 
> 	Sam
> 
> > ---
> >  drivers/video/fbdev/core/fbmem.c | 8 ++++++--
> >  include/linux/fb.h               | 7 +++----
> >  2 files changed, 9 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> > index 904ef1250677..dad6572942fa 100644
> > --- a/drivers/video/fbdev/core/fbmem.c
> > +++ b/drivers/video/fbdev/core/fbmem.c
> > @@ -48,10 +48,14 @@
> >  static DEFINE_MUTEX(registration_lock);
> >  
> >  struct fb_info *registered_fb[FB_MAX] __read_mostly;
> > -EXPORT_SYMBOL(registered_fb);
> > -
> >  int num_registered_fb __read_mostly;
> > +#if IS_ENABLED(CONFIG_OLPC_DCON)
> > +EXPORT_SYMBOL(registered_fb);
> >  EXPORT_SYMBOL(num_registered_fb);
> > +#endif
> > +#define for_each_registered_fb(i)		\
> > +	for (i = 0; i < FB_MAX; i++)		\
> > +		if (!registered_fb[i]) {} else
> >  
> >  bool fb_center_logo __read_mostly;
> >  
> > diff --git a/include/linux/fb.h b/include/linux/fb.h
> > index a8a00d2ba1f3..e236817502c2 100644
> > --- a/include/linux/fb.h
> > +++ b/include/linux/fb.h
> > @@ -622,16 +622,15 @@ extern int fb_get_color_depth(struct fb_var_screeninfo *var,
> >  extern int fb_get_options(const char *name, char **option);
> >  extern int fb_new_modelist(struct fb_info *info);
> >  
> > +#if IS_ENABLED(CONFIG_OLPC_DCON)
> >  extern struct fb_info *registered_fb[FB_MAX];
> > +
> >  extern int num_registered_fb;
> > +#endif
> >  extern bool fb_center_logo;
> >  extern int fb_logo_count;
> >  extern struct class *fb_class;
> >  
> > -#define for_each_registered_fb(i)		\
> > -	for (i = 0; i < FB_MAX; i++)		\
> > -		if (!registered_fb[i]) {} else
> > -
> >  static inline void lock_fb_info(struct fb_info *info)
> >  {
> >  	mutex_lock(&info->lock);
> > -- 
> > 2.33.0
Daniel Vetter Feb. 8, 2022, 8:59 p.m. UTC | #6 
On Tue, Feb 08, 2022 at 03:04:51PM +0100, Daniel Vetter wrote:
> On Fri, Feb 04, 2022 at 09:30:56AM +0100, Geert Uytterhoeven wrote:
> > Hi Daniel,
> > 
> > Thanks for your patch!
> > 
> > On Tue, Feb 1, 2022 at 9:50 PM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> > > Well except when the olpc dcon fbdev driver is enabled, that thing
> > > digs around in there in rather unfixable ways.
> > 
> > Can't the actual frame buffer driver (which one?) used on olpc export
> > a pointer to its fb_info?
> 
> Yeah that might be the right thing to do, I'll add that as a stagin TODO
> in the next iteration.

Well I tried to do that and noticed I've done that already in 2019:

commit af1440368837f19ac7d5dec05d929d91308f5a90
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue May 28 11:03:03 2019 +0200

    staging/olpc_dcon: Add drm conversion to TODO

TODO already explains how this should be done correctly in drm. Well maybe
we should add that stitching the drivers together should be done with
component.c or something like that.
-Daniel

> 
> > 
> > > --- a/drivers/video/fbdev/core/fbmem.c
> > > +++ b/drivers/video/fbdev/core/fbmem.c
> > > @@ -48,10 +48,14 @@
> > >  static DEFINE_MUTEX(registration_lock);
> > >
> > >  struct fb_info *registered_fb[FB_MAX] __read_mostly;
> > > -EXPORT_SYMBOL(registered_fb);
> > > -
> > >  int num_registered_fb __read_mostly;
> > > +#if IS_ENABLED(CONFIG_OLPC_DCON)
> > 
> > CONFIG_FB_OLPC_DCON (everywhere), cfr. the build failure reported
> > by the robot.
> 
> Yeah realized that too and fixed it locally.
> 
> Cheers, Daniel
> 
> > 
> > Gr{oetje,eeting}s,
> > 
> >                         Geert
> > 
> > --
> > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> > 
> > In personal conversations with technical people, I call myself a hacker. But
> > when I'm talking to journalists I just say "programmer" or something like that.
> >                                 -- Linus Torvalds
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
diff mbox series

Patch

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 904ef1250677..dad6572942fa 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -48,10 +48,14 @@ 
 static DEFINE_MUTEX(registration_lock);
 
 struct fb_info *registered_fb[FB_MAX] __read_mostly;
-EXPORT_SYMBOL(registered_fb);
-
 int num_registered_fb __read_mostly;
+#if IS_ENABLED(CONFIG_OLPC_DCON)
+EXPORT_SYMBOL(registered_fb);
 EXPORT_SYMBOL(num_registered_fb);
+#endif
+#define for_each_registered_fb(i)		\
+	for (i = 0; i < FB_MAX; i++)		\
+		if (!registered_fb[i]) {} else
 
 bool fb_center_logo __read_mostly;
 
diff --git a/include/linux/fb.h b/include/linux/fb.h
index a8a00d2ba1f3..e236817502c2 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -622,16 +622,15 @@  extern int fb_get_color_depth(struct fb_var_screeninfo *var,
 extern int fb_get_options(const char *name, char **option);
 extern int fb_new_modelist(struct fb_info *info);
 
+#if IS_ENABLED(CONFIG_OLPC_DCON)
 extern struct fb_info *registered_fb[FB_MAX];
+
 extern int num_registered_fb;
+#endif
 extern bool fb_center_logo;
 extern int fb_logo_count;
 extern struct class *fb_class;
 
-#define for_each_registered_fb(i)		\
-	for (i = 0; i < FB_MAX; i++)		\
-		if (!registered_fb[i]) {} else
-
 static inline void lock_fb_info(struct fb_info *info)
 {
 	mutex_lock(&info->lock);