Re: [PATCH] of: Make of framebuffer devices unique

[Thomas Zimmermann]

Hi Michal,




Am 18.01.23 um 22:46 schrieb Michal Suchánek:

thanks for fixing this issue. But the review time was way too short. Please see my comments below.

On Wed, Jan 18, 2023 at 09:13:05PM +0100, Erhard F. wrote:

On Tue, 17 Jan 2023 17:58:04 +0100
Michal Suchanek <msucha...@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@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. <erhar...@mailbox.org>
Suggested-by: Thomas Zimmermann <tzimmerm...@suse.de>
Signed-off-by: Michal Suchanek <msucha...@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;

@@ -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++);

/* Check if we have a MacOS display without a node spec */

Best regards
Thomas

Platform devices use a single dot (.) as separator before the index. Counting starts at zero. See /sys/bus/platform/ for examples. Can we please stick with that scheme? Generated names would then be of-display.0, of-display.1, etc.

+                       if (ret >= sizeof(buf))
+                               continue;
+                       of_platform_device_create(node, buf, NULL);
                }

--
2.35.3

} else {

Thank you for the patch Michal!

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

Indeed, it's doubly bad.

Where is the kernel test robot when you need it?

It should not be that easy to miss this file but clearly it can happen.

I will send a fixup.

Sorry about the mess.

Thanks

Michal

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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