[PATCH] of: Make of framebuffer devices unique

Erhard F. erhard_f at mailbox.org
Thu Jan 19 07:13:05 AEDT 2023


On Tue, 17 Jan 2023 17:58:04 +0100
Michal Suchanek <msuchanek at suse.de> wrote:

> Since Linux 5.19 this error is observed:
> 
> sysfs: cannot create duplicate filename '/devices/platform/of-display'
> 
> This is because multiple devices with the same name 'of-display' are
> created on the same bus.
> 
> Update the code to create numbered device names for the non-boot
> disaplay.
> 
> cc: linuxppc-dev at lists.ozlabs.org
> References: https://bugzilla.kernel.org/show_bug.cgi?id=216095
> Fixes: 52b1b46c39ae ("of: Create platform devices for OF framebuffers")
> Reported-by: Erhard F. <erhard_f at mailbox.org>
> Suggested-by: Thomas Zimmermann <tzimmermann at suse.de>
> Signed-off-by: Michal Suchanek <msuchanek at suse.de>
> ---
>  drivers/of/platform.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 81c8c227ab6b..f2a5d679a324 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -525,6 +525,7 @@ static int __init of_platform_default_populate_init(void)
>  	if (IS_ENABLED(CONFIG_PPC)) {
>  		struct device_node *boot_display = NULL;
>  		struct platform_device *dev;
> +		int display_number = 1;
>  		int ret;
>  
>  		/* Check if we have a MacOS display without a node spec */
> @@ -561,10 +562,15 @@ static int __init of_platform_default_populate_init(void)
>  			boot_display = node;
>  			break;
>  		}
> +
>  		for_each_node_by_type(node, "display") {
> +			char *buf[14];
>  			if (!of_get_property(node, "linux,opened", NULL) || node == boot_display)
>  				continue;
> -			of_platform_device_create(node, "of-display", NULL);
> +			ret = snprintf(buf, "of-display-%d", display_number++);
> +			if (ret >= sizeof(buf))
> +				continue;
> +			of_platform_device_create(node, buf, NULL);
>  		}
>  
>  	} else {
> -- 
> 2.35.3
> 

Thank you for the patch Michal!

It applies on 6.2-rc4 but I get this build error with my config:

 # make
  CALL    scripts/checksyscalls.sh
  CC      drivers/of/platform.o
drivers/of/platform.c: In function 'of_platform_default_populate_init':
drivers/of/platform.c:570:40: error: passing argument 1 of 'snprintf' from incompatible pointer type [-Werror=incompatible-pointer-types]
  570 |                         ret = snprintf(buf, "of-display-%d", display_number++);
      |                                        ^~~
      |                                        |
      |                                        char **
In file included from ./arch/powerpc/include/asm/page.h:11,
                 from ./arch/powerpc/include/asm/thread_info.h:13,
                 from ./include/linux/thread_info.h:60,
                 from ./arch/powerpc/include/asm/ptrace.h:342,
                 from ./arch/powerpc/include/asm/hw_irq.h:12,
                 from ./arch/powerpc/include/asm/irqflags.h:12,
                 from ./include/linux/irqflags.h:16,
                 from ./include/asm-generic/cmpxchg-local.h:6,
                 from ./arch/powerpc/include/asm/cmpxchg.h:755,
                 from ./arch/powerpc/include/asm/atomic.h:11,
                 from ./include/linux/atomic.h:7,
                 from ./include/linux/mm_types_task.h:13,
                 from ./include/linux/mm_types.h:5,
                 from ./include/linux/buildid.h:5,
                 from ./include/linux/module.h:14,
                 from drivers/of/platform.c:13:
./include/linux/kernel.h:213:20: note: expected 'char *' but argument is of type 'char **'
  213 | int snprintf(char *buf, size_t size, const char *fmt, ...);
      |              ~~~~~~^~~
drivers/of/platform.c:570:45: warning: passing argument 2 of 'snprintf' makes integer from pointer without a cast [-Wint-conversion]
  570 |                         ret = snprintf(buf, "of-display-%d", display_number++);
      |                                             ^~~~~~~~~~~~~~~
      |                                             |
      |                                             char *
./include/linux/kernel.h:213:32: note: expected 'size_t' {aka 'unsigned int'} but argument is of type 'char *'
  213 | int snprintf(char *buf, size_t size, const char *fmt, ...);
      |                         ~~~~~~~^~~~
drivers/of/platform.c:570:76: warning: passing argument 3 of 'snprintf' makes pointer from integer without a cast [-Wint-conversion]
  570 |                         ret = snprintf(buf, "of-display-%d", display_number++);
      |                                                              ~~~~~~~~~~~~~~^~
      |                                                                            |
      |                                                                            int
./include/linux/kernel.h:213:50: note: expected 'const char *' but argument is of type 'int'
  213 | int snprintf(char *buf, size_t size, const char *fmt, ...);
      |                                      ~~~~~~~~~~~~^~~
drivers/of/platform.c:573:57: error: passing argument 2 of 'of_platform_device_create' from incompatible pointer type [-Werror=incompatible-pointer-types]
  573 |                         of_platform_device_create(node, buf, NULL);
      |                                                         ^~~
      |                                                         |
      |                                                         char **
drivers/of/platform.c:211:57: note: expected 'const char *' but argument is of type 'char **'
  211 |                                             const char *bus_id,
      |                                             ~~~~~~~~~~~~^~~~~~
cc1: some warnings being treated as errors
make[3]: *** [scripts/Makefile.build:252: drivers/of/platform.o] Fehler 1
make[2]: *** [scripts/Makefile.build:504: drivers/of] Fehler 2
make[1]: *** [scripts/Makefile.build:504: drivers] Fehler 2
make: *** [Makefile:2008: .] Error 2


Regards,
Erhard
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