Re: keyboard backlight max_brightness bug on Dell Latitude E6410

Pali Rohár
2017-09-29T14:11:31Z

Yes, that would fix problem for you and break other machines...

On Friday 29 September 2017 07:08:23 Gabriel M. Elder wrote:
> FYI, latest update and info relating to
> https://bugzilla.kernel.org/show_bug.cgi?id=196913
>
>
> --- a/drivers/platform/x86/dell-laptop.c
> +++ a/drivers/platform/x86/dell-laptop.c
> @@ -1217,7 +1217,7 @@ static int kbd_get_info(struct kbd_info *info)
> static unsigned int kbd_get_max_level(void)
> {
> if (kbd_info.levels != 0)
> - return kbd_info.levels;
> + return kbd_info.levels - 1;
> if (kbd_mode_levels_count > 0)
> return kbd_mode_levels_count - 1;
> return 0;
>
>
> Finally had a chance to make this mod, compile and try it out. Based on
> my testing, it seems to completely correct the problem.
>
> Upon initially opening the power panel in gnome-control-center, the
> keyboard brightness slider is all the way over to the right, where one
> would expect it to be, as well as all of the brightness step levels.
> Closing the lid, putting it to sleep and waking it back up does not have
> the annoying keyboard backlight disabling side-effect that I previously
> described.
>
> - Gabriel
>
>
> -------- Original Message --------
> Subject: Re: keyboard backlight max_brightness bug on Dell Latitude
> E6410
> From: Pali Rohár <pali.rohar@gmail.com>
> Date: Thu, September 14, 2017 10:25 am
> To: Gabriele Mazzotta <gabriele.mzt@gmail.com>, Mario Limonciello
> <Mario_Limonciello@Dell.com>
> Cc: "Gabriel M. Elder" <gabriel@tekgnowsys.com>, Darren Hart
> <dvhart@infradead.org>, andy@infradead.org,
> "platform-driver-x86@vger.kernel.org"
> <platform-driver-x86@vger.kernel.org>, "linux-kernel@vger.kernel.org"
> <linux-kernel@vger.kernel.org>
>
> On Thursday 14 September 2017 16:33:57 Gabriele Mazzotta wrote:
> > 2017-09-14 15:54 GMT+02:00 Pali Rohár <pali.rohar@gmail.com>:
> > > Adding Gabriele to thread, IIRC you have machine which uses
> > > "supported keyboard light brightness levels"
> > > Can you look at this bug, if your machine is affected by it too?
> >
> > My keyboard has two brightness levels + off. The value of
> > max_brightness is 2, as expected.
>
> Ah :-(
>
> So you have "Supported Keyboard light brightness levels : 2" and you
> can se value 0, 1 or 2.
>
> And Gabriel has "Supported Keyboard light brightness levels : 10" and
> can set only values 0..9. But not 10.
>
> Any idea how to solve this situation?
>
> CCing Mario from Dell. Can you recheck what is wrong here? Or why
> Dell Latitude E6410 behaves differently?
>
> > Gabriele
> >
> > Yes, my laptop uses "supported keyboard light brightness levels".
> > >
> > > Important parts in ouptput:
> > >
> > >> ... --info
> > >> Supported Keyboard light brightness levels : 10
> > >
> > >> ... --get-status
> > >> Current keyboard light level : 9
> > >
> > > Gabriel, can you play with this tool, which values can be set via
> > > --set-level= parameter? Is 10 accepted? --get-status can be used to
> > > check if value was accepted.
> > >
> > > On Thursday 14 September 2017 06:35:15 Gabriel M. Elder wrote:
> > >>
> > >> output from smbios-keyboard-ctl --info:
> > >>
> > >> Libsmbios version : 2.3.0
> > >> smbios-keyboard-ctl version : 2.3.0
> > >>
> > >> Capabilities of KeyBoard Illumination on your system:
> > >> -------------------------------------------------------------------
> > >> Supported USER Selectable Modes :
> > >> Always OFF
> > >> Auto: ALS- and input-activity-based On; input-activity based Off
> > >> Auto: Input-activity-based On; input-activity based Off
> > >>
> > >> Supported Keyboard illumination type : Backlight
> > >>
> > >> Supports Keyboard illumination on :
> > >> Any Keystroke
> > >> Touchpad activity
> > >> Pointing stick
> > >>
> > >> Can configure Keyboard illumination timeout unit in :
> > >> Seconds
> > >> Minutes
> > >> Hours
> > >>
> > >> Supported Keyboard light brightness levels : 10
> > >>
> > >> Maximum acceptable seconds timeout value : 255
> > >>
> > >> Maximum acceptable minutes timeout value : 255
> > >>
> > >> Maximum acceptable hours timeout value : 12
> > >>
> > >> Maximum acceptable days timeout value : 0
> > >>
> > >>
> > >> output from smbios-keyboard-ctl --get-status:
> > >>
> > >> Helper function to print current status of keyboard illumination
> > >>
> > >> Current status of KeyBoard Illumination setting on your system:
> > >> -------------------------------------------------------------------
> > >>
> > >> Configured mode state:
> > >> Auto: Input-activity-based On; input-activity based Off
> > >>
> > >> Your Keyboard will illumination on:
> > >> Any Keystroke
> > >> Touchpad activity
> > >> Pointing stick
> > >>
> > >> Keyboard illumination timeout has bee set at: 10 Seconds
> > >>
> > >> Current setting of ALS value that turns the light on or off: 18
> > >> Current ALS Reading : 16
> > >> Current keyboard light level : 9
> > >>
> > >>
> > >> -------- Original Message --------
> > >> Subject: Re: keyboard backlight max_brightness bug on Dell Latitude
> > >> E6410
> > >> From: Pali Rohár <pali.rohar@gmail.com>
> > >> Date: Thu, September 14, 2017 3:06 am
> > >> To: "Gabriel M. Elder" <gabriel@tekgnowsys.com>
> > >> Cc: dvhart@infradead.org, andy@infradead.org,
> > >> platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org
> > >>
> > >> On Monday 11 September 2017 23:25:27 Gabriel M. Elder wrote:
> > >> > Hi all,
> > >> > Hans de Goede, one of the upower maintainers, suggested I alert you all to this bug:
> > >> >
> > >> > https://bugs.freedesktop.org/show_bug.cgi?id=100041
> > >> >
> > >> > and the new one I filed via the kernel bugzilla:
> > >> >
> > >> > https://bugzilla.kernel.org/show_bug.cgi?id=196913
> > >> > "keyboard backlight max_brightness value outside allowable range on Dell Latitude E6410 laptop"
> > >> >
> > >> > Please check it out at your earliest convenience.
> > >> >
> > >> > thanks,
> > >> > - Gabriel
> > >>
> > >> Hi Gabriel, please avoid sending such html emails to mailing list as it
> > >> is hard to read them and also you have a very big chance that email
> > >> would be eaten by spam filter or other developers would completely
> > >> ignore it...
> > >>
> > >> To debug your problem, can you run smbios-keyboard-ctl tool from the
> > >> libsmbios project? https://github.com/dell/libsmbios
> > >>
> > >> We would need output from --info parameter and also from --get-status.
> > >>
> > >
> > > --
> > > Pali Rohár
> > > pali.rohar@gmail.com