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Date:   Tue, 21 Nov 2023 10:56:34 +0100
Message-ID: <87bkbno2el.wl-tiwai@suse.de>
From:   Takashi Iwai <tiwai@suse.de>
To:     Thorsten Leemhuis <regressions@leemhuis.info>
Cc:     Takashi Iwai <tiwai@suse.de>,
        Jean-Jacques Hiblot <jjhiblot@traphandler.com>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Regressions <regressions@lists.linux.dev>,
        Linux LEDs <linux-leds@vger.kernel.org>,
        Tim Crawford <tcrawford@system76.com>,
        Jeremy Soller <jeremy@system76.com>,
        System76 Product Development <productdev@system76.com>,
        Lee Jones <lee@kernel.org>, Pavel Machek <pavel@ucw.cz>,
        Johannes =?ISO-8859-1?Q?Pe?= =?ISO-8859-1?Q?n=DFel?= 
        <johannes.penssel@gmail.com>
Subject: Re: Fwd: sysfs: cannot create duplicate filename .../system76_acpi::kbd_backlight/color
In-Reply-To: <87edgjo2kr.wl-tiwai@suse.de>
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        <87sf50pm34.wl-tiwai@suse.de>
        <b9d4ab02-fe49-48ab-bf74-0c7a578e891a@leemhuis.info>
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On Tue, 21 Nov 2023 10:52:52 +0100,
Takashi Iwai wrote:
> 
> On Tue, 21 Nov 2023 10:19:03 +0100,
> Thorsten Leemhuis wrote:
> > 
> > Takashi, Jean-Jacques Hiblot, Lee,
> > 
> > On 20.11.23 14:53, Takashi Iwai wrote:
> > > On Mon, 06 Nov 2023 14:19:08 +0100,
> > > Bagas Sanjaya wrote:
> > >> On Sat, Nov 04, 2023 at 01:01:56PM +0100, Jean-Jacques Hiblot wrote:
> > >>> On 29/10/2023 02:48, Bagas Sanjaya wrote:
> > >>>> On Thu, Oct 26, 2023 at 02:55:06PM +0700, Bagas Sanjaya wrote:
> > >>>>> The culprit seems to be commit c7d80059b086c4986cd994a1973ec7a5d75f8eea, which introduces a new 'color' attribute for led sysfs class devices. The problem is that the system76-acpi platform driver tries to create the exact same sysfs attribute itself for the system76_acpi::kbd_backlight device, leading to the conflict. For testing purposes, I've just rebuilt the kernel with the system76-apci color attribute renamed to kb_color, and that fixes the issue.
> > >>>>
> > >>>> Jean-Jacques Hiblot, would you like to take a look on this regression,
> > >>>> since you authored the culprit?
> > >
> > >>> The offending commit stores the color in struct led_classdev and exposes it
> > >>> via sysfs. It was part of a series that create a RGB leds from multiple
> > >>> single-color LEDs. for this series, we need the color information but we
> > >>> don't really need to expose it it via sysfs. In order to fix the issue, we
> > >>> can remove the 'color' attribute from the sysfs.
> > >>
> > >> OK, see you in the patch!
> > > 
> > > Is there a patch available?
> > 
> > Not that I know of. Could not find anything on lore either.
> > 
> > > This bug hits for a few Logitech keyboard models, too, and it makes
> > > 6.6 kernel unsable for them, as hid-lg-g15 driver probe fails due to
> > > this bug:
> > >   https://bugzilla.kernel.org/show_bug.cgi?id=218155
> > > 
> > > We need a quick fix for 6.6.x.
> > 
> > Given that Jean-Jacques Hiblot (the author of the culprit) and Lee (who
> > committed it and sent it to Linus) know about this for a while already
> > without doing anything about it, I wonder if someone should just send a
> > revert to Linus (unless of course that is likely to introduce a
> > regression on its own).
> > 
> > Takashi, could you maybe do this, unless a fix shows up real soon?
> 
> I can, but we need to decide which way to go.
> There are several options:
> 
> 1. Revert the commit c7d80059b086;
>    this drops led class color sysfs entries.  Also the store of
>    led_cdev->color from fwnode is dropped, too.
> 
> 2. Drop only led class color sysfs entries;
>    a partial revert of c7d80059b086 above
> 
> 3. Rename conflicting sysfs entries in drivers;
>    e.g. color -> kb_color for hid-lg-g15 and system76_acpi

... and

4. Rename conflicting sysfs class color entry

> In either way, we'd break user-space (sysfs).

It still holds :)


Takashi