Re: [PATCH 2/2] drm/ofdrm: Update expected device name

From: Thomas Zimmermann
Date: Mon Apr 24 2023 - 05:08:01 EST


Hi

Am 24.04.23 um 09:33 schrieb Geert Uytterhoeven:
Hi Cyril,

CC DT

On Wed, Apr 12, 2023 at 12:05 PM Cyril Brulebois <cyril@xxxxxxxxxxx> wrote:
Since commit 241d2fb56a18 ("of: Make OF framebuffer device names unique"),
as spotted by Frédéric Bonnard, the historical "of-display" device is
gone: the updated logic creates "of-display.0" instead, then as many
"of-display.N" as required.

This means that offb no longer finds the expected device, which prevents
the Debian Installer from setting up its interface, at least on ppc64el.

Given the code similarity it is likely to affect ofdrm in the same way.

It might be better to iterate on all possible nodes, but updating the
hardcoded device from "of-display" to "of-display.0" is likely to help
as a first step.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217328
Link: https://bugs.debian.org/1033058
Fixes: 241d2fb56a18 ("of: Make OF framebuffer device names unique")
Cc: stable@xxxxxxxxxxxxxxx # v6.2+
Signed-off-by: Cyril Brulebois <cyril@xxxxxxxxxxx>

Thanks for your patch, which is now commit 3a9d8ea2539ebebd
("drm/ofdrm: Update expected device name") in fbdev/for-next.

--- a/drivers/gpu/drm/tiny/ofdrm.c
+++ b/drivers/gpu/drm/tiny/ofdrm.c
@@ -1390,7 +1390,7 @@ MODULE_DEVICE_TABLE(of, ofdrm_of_match_display);

static struct platform_driver ofdrm_platform_driver = {
.driver = {
- .name = "of-display",
+ .name = "of-display.0",
.of_match_table = ofdrm_of_match_display,
},
.probe = ofdrm_probe,

Same comment as for "[PATCH 1/2] fbdev/offb: Update expected device
name".

https://lore.kernel.org/r/CAMuHMdVGEeAsmb4tAuuqqGJ-4+BBETwEwYJA+M9NyJv0BJ_hNg@xxxxxxxxxxxxxx

Sorry that I missed this patch. I agree that it's probably not correct. At least in ofdrm, we want to be able to use multiple framebuffers at the same time; a feature that has been broken by this change.

Best regards
Thomas


Gr{oetje,eeting}s,

Geert


--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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