2019-09-23 15:52:21

by Pali Rohár

[permalink] [raw]
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 <[email protected]>
> >
> > --
> > Pali Rohr
> > [email protected]
>
> --
> Pacien TRAN-GIRARD <[email protected]>

--
Pali Rohár
[email protected]


Attachments:
(No filename) (1.65 kB)
signature.asc (201.00 B)
Download all attachments

2019-09-24 17:11:54

by Mario Limonciello

[permalink] [raw]
Subject: RE: [PATCH] platform/x86: dell-laptop: fix phantom kbd backlight on Inspiron 10xx

> -----Original Message-----
> From: Pali Rohár <[email protected]>
> Sent: Sunday, September 22, 2019 8:43 AM
> To: Pacien TRAN-GIRARD
> Cc: Matthew Garrett; Darren Hart; Andy Shevchenko; platform-driver-
> [email protected]; [email protected]; Limonciello, Mario
> 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.
>

I agree an Inspiron is unlikely to be updated 9 years later. I think the right thing
to do in this instance is to blacklist this particular platform in kernel driver.

> > >
> > > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107651
> > > > Signed-off-by: Pacien TRAN-GIRARD <[email protected]>
> > >
> > > --
> > > Pali Rohr
> > > [email protected]
> >
> > --
> > Pacien TRAN-GIRARD <[email protected]>
>
> --
> Pali Rohár
> [email protected]

2019-09-26 09:19:49

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH] platform/x86: dell-laptop: fix phantom kbd backlight on Inspiron 10xx

On Mon, Sep 23, 2019 at 4:24 PM <[email protected]> wrote:
> > From: Pali Rohár <[email protected]>
> > Sent: Sunday, September 22, 2019 8:43 AM
> > To: Pacien TRAN-GIRARD
> > Cc: Matthew Garrett; Darren Hart; Andy Shevchenko; platform-driver-
> > [email protected]; [email protected]; Limonciello, Mario
> > Subject: Re: [PATCH] platform/x86: dell-laptop: fix phantom kbd backlight on
> > Inspiron 10xx

> > We need to wait what Mario wrote about this particular problem.
> >
>
> I agree an Inspiron is unlikely to be updated 9 years later. I think the right thing
> to do in this instance is to blacklist this particular platform in kernel driver.

Does it mean you are okay with the proposed patch? Can you give your tag then?

--
With Best Regards,
Andy Shevchenko

2019-09-26 09:20:53

by Pali Rohár

[permalink] [raw]
Subject: Re: [PATCH] platform/x86: dell-laptop: fix phantom kbd backlight on Inspiron 10xx

On Wednesday 25 September 2019 11:07:35 Andy Shevchenko wrote:
> On Mon, Sep 23, 2019 at 4:24 PM <[email protected]> wrote:
> > > From: Pali Rohár <[email protected]>
> > > Sent: Sunday, September 22, 2019 8:43 AM
> > > To: Pacien TRAN-GIRARD
> > > Cc: Matthew Garrett; Darren Hart; Andy Shevchenko; platform-driver-
> > > [email protected]; [email protected]; Limonciello, Mario
> > > Subject: Re: [PATCH] platform/x86: dell-laptop: fix phantom kbd backlight on
> > > Inspiron 10xx
>
> > > We need to wait what Mario wrote about this particular problem.
> > >
> >
> > I agree an Inspiron is unlikely to be updated 9 years later. I think the right thing
> > to do in this instance is to blacklist this particular platform in kernel driver.
>
> Does it mean you are okay with the proposed patch? Can you give your tag then?

I would rather use different name as kbd_phantom_backlight. E.g.
lbd_broken_backlight or something which indicates non-working / disabled
support.

Also in commit message is written that problem is with KBD_LED_OFF_TOKEN
and KBD_LED_ON_TOKEN tokens, but proposed patch does not blacklist these
tokens, but rather turn off whole kbd functionality. So proposed patch
does not patch commit message, nor explain it.

--
Pali Rohár
[email protected]