linux-kernel - Re: [PATCH] platform/x86: dell-laptop: fix phantom kbd backlight on Inspiron 10xx

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Date:   Sun, 22 Sep 2019 15:43:23 +0200
From:   Pali Rohár <pali.rohar@...il.com>
To:     Pacien TRAN-GIRARD <pacien.trangirard@...ien.net>
Cc:     Matthew Garrett <mjg59@...f.ucam.org>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        mario.limonciello@...l.com
Subject: Re: [PATCH] platform/x86: dell-laptop: fix phantom kbd backlight on
 Inspiron 10xx

On Wednesday 18 September 2019 17:29:15 Pacien TRAN-GIRARD wrote:
> Quoting Pali Rohár (2019-09-12 09:33:58)
> > On Thursday 12 September 2019 01:14:48 Pacien TRAN-GIRARD wrote:
> > > This patch registers a quirk disabling keyboard backlight support
> > > for the Dell Inspiron 1012 and 1018.
> > > 
> > > Those models wrongly report supporting the KBD_LED_OFF_TOKEN and
> > > KBD_LED_ON_TOKEN SMBIOS tokens, exposing keyboard brightness controls
> > > through sysfs which freeze the system when used.
> > > 
> > > The associated SMBIOS calls never return and cause the system to
> > > hang, notably at boot when systemd-backlight tries to restore
> > > previous brightness settings.
> > 
> > Hi! This sounds like a firmware bug. Have you already reported it to Dell?
> 
> Yes, the issue has been reported to Dell's technical support, which didn't
> provide a satisfying answer.

There were already some firmware problems with keyboard backlight and
Mario posted this comment about Linux support:
https://github.com/dell/libsmbios/issues/48#issuecomment-391328501

Can you try to use libsmbios tools and if they do not work too, report
problem also there?

> I'm not familiar with Dell's policy, but I doubt that they would issue a
> BIOS update for discontinued models from 2010.

We need to wait what Mario wrote about this particular problem.

> > 
> > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107651
> > > Signed-off-by: Pacien TRAN-GIRARD <pacien.trangirard@...ien.net>
> > 
> > -- 
> > Pali Rohr
> > pali.rohar@...il.com
> 
> --
> Pacien TRAN-GIRARD <pacien.trangirard@...ien.net>

-- 
Pali Rohár
pali.rohar@...il.com

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