Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)

Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)

[Tom St Denis]

Hello all,

Somewhere between v3.6.8 [vanilla] and 3.7.0-rc7 the ability to control the LCD brightness was broken on this laptop [details below].  Basically it locks the brightness as full brightness and cannot be changed.  It works properly in v3.6.8 though [and below...].

Details:

00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09) (prog-if 00 [VGA controller])
	Subsystem: Dell Device 056e
	Flags: bus master, fast devsel, latency 0, IRQ 44
	Memory at c3000000 (64-bit, non-prefetchable) [size=4M]
	Memory at b0000000 (64-bit, prefetchable) [size=256M]
	I/O ports at 5000 [size=64]
	Expansion ROM at <unassigned> [disabled]
	Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
	Capabilities: [d0] Power Management version 2
	Capabilities: [a4] PCI Advanced Features
	Kernel driver in use: i915

This is on a Dell Vostro 3560/0C05GV

I have the discrete radeon turned off [via vgaswitcheroo].  I have dell_wmi and dell_laptop loaded.  I use the same kernel config between the two builds.

Tom

Re: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)

[Tom St Denis]

I've narrowed it down to sometime between v3.6.8 and v3.7-rc1.  So none of the v3.7 series will work with this GPU/panel.

I don't think it has anything to do with the dell modules since they haven't changed.

Tom


----- Original Message -----
> From: "Tom St Denis" <tstdenis@elliptictech.com>
> To: linux-kernel@vger.kernel.org
> Cc: "daniel vetter" <daniel.vetter@ffwll.ch>, mjg59@srcf.ucam.org
> Sent: Saturday, 1 December, 2012 6:49:51 PM
> Subject: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)
> 
> Hello all,
> 
> Somewhere between v3.6.8 [vanilla] and 3.7.0-rc7 the ability to
> control the LCD brightness was broken on this laptop [details
> below].  Basically it locks the brightness as full brightness and
> cannot be changed.  It works properly in v3.6.8 though [and
> below...].
> 
> Details:
> 
> 00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core
> processor Graphics Controller (rev 09) (prog-if 00 [VGA controller])
> 	Subsystem: Dell Device 056e
> 	Flags: bus master, fast devsel, latency 0, IRQ 44
> 	Memory at c3000000 (64-bit, non-prefetchable) [size=4M]
> 	Memory at b0000000 (64-bit, prefetchable) [size=256M]
> 	I/O ports at 5000 [size=64]
> 	Expansion ROM at <unassigned> [disabled]
> 	Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
> 	Capabilities: [d0] Power Management version 2
> 	Capabilities: [a4] PCI Advanced Features
> 	Kernel driver in use: i915
> 
> This is on a Dell Vostro 3560/0C05GV
> 
> I have the discrete radeon turned off [via vgaswitcheroo].  I have
> dell_wmi and dell_laptop loaded.  I use the same kernel config
> between the two builds.
> 
> Tom

Re: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)

[Daniel Vetter]

On Sun, Dec 2, 2012 at 12:32 PM, Tom St Denis <tstdenis@elliptictech.com> wrote:
> I've narrowed it down to sometime between v3.6.8 and v3.7-rc1.  So none of the v3.7 series will work with this GPU/panel.

Hm, that's still a few hundred relevant commits intermingled with a
few thousand that likely don't matter ;-) Can you please attempt a
kernel bisect with git? For a nice howto check out
http://www.reactivated.net/weblog/archives/2006/01/using-git-bisect-to-find-buggy-kernel-patches/

Also, can you please check which of the different backlight controls
in /sys/class/backlight work on 3.6 (and whether any of them still
work on 3.7)?

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)

[Daniel Vetter]

Including a bunch more lists to the cc.

On Sun, Dec 2, 2012 at 12:42 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> On Sun, Dec 2, 2012 at 12:32 PM, Tom St Denis <tstdenis@elliptictech.com> wrote:
>> I've narrowed it down to sometime between v3.6.8 and v3.7-rc1.  So none of the v3.7 series will work with this GPU/panel.
>
> Hm, that's still a few hundred relevant commits intermingled with a
> few thousand that likely don't matter ;-) Can you please attempt a
> kernel bisect with git? For a nice howto check out
> http://www.reactivated.net/weblog/archives/2006/01/using-git-bisect-to-find-buggy-kernel-patches/
>
> Also, can you please check which of the different backlight controls
> in /sys/class/backlight work on 3.6 (and whether any of them still
> work on 3.7)?
>
> Thanks, Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)

[Tom St Denis]

Ok so on v3.7-rc1 [and I suspect up] I can manually control the brightness by echoing to 

/sys/class/backlight/intel_backlight/brightness

But I still can't use the buttons to control it (it only goes one tick down from max and stops there).  I'm using GNOME3 from a x86_64 unstable debian install [up to date with latest].

I just noticed that under v3.7 I have a new directory /sys/class/backlight/acpi_video1 which is what GNOME is actually controlling.  I can't disable ACPI video control so is there a workaround?

Tom



----- Original Message -----
> From: "Daniel Vetter" <daniel.vetter@ffwll.ch>
> To: "Tom St Denis" <tstdenis@elliptictech.com>
> Cc: linux-kernel@vger.kernel.org, "intel-gfx" <intel-gfx@lists.freedesktop.org>, "dri-devel"
> <dri-devel@lists.freedesktop.org>
> Sent: Sunday, 2 December, 2012 6:43:14 AM
> Subject: Re: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)
> 
> Including a bunch more lists to the cc.
> 
> On Sun, Dec 2, 2012 at 12:42 PM, Daniel Vetter
> <daniel.vetter@ffwll.ch> wrote:
> > On Sun, Dec 2, 2012 at 12:32 PM, Tom St Denis
> > <tstdenis@elliptictech.com> wrote:
> >> I've narrowed it down to sometime between v3.6.8 and v3.7-rc1.  So
> >> none of the v3.7 series will work with this GPU/panel.
> >
> > Hm, that's still a few hundred relevant commits intermingled with a
> > few thousand that likely don't matter ;-) Can you please attempt a
> > kernel bisect with git? For a nice howto check out
> > http://www.reactivated.net/weblog/archives/2006/01/using-git-bisect-to-find-buggy-kernel-patches/
> >
> > Also, can you please check which of the different backlight
> > controls
> > in /sys/class/backlight work on 3.6 (and whether any of them still
> > work on 3.7)?
> >
> > Thanks, Daniel
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> 
> 
> 
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> 

Re: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)

[Daniel Vetter]

On Sun, Dec 2, 2012 at 2:49 PM, Tom St Denis <tstdenis@elliptictech.com> wrote:
> Ok so on v3.7-rc1 [and I suspect up] I can manually control the brightness by echoing to
>
> /sys/class/backlight/intel_backlight/brightness
>
> But I still can't use the buttons to control it (it only goes one tick down from max and stops there).  I'm using GNOME3 from a x86_64 unstable debian install [up to date with latest].
>
> I just noticed that under v3.7 I have a new directory /sys/class/backlight/acpi_video1 which is what GNOME is actually controlling.  I can't disable ACPI video control so is there a workaround?

Hah, acpi registered a broken backlight driver, which overwrites the
intel backlight - for once it's not i915.ko's fault ;-) For a
workaround either disable the acpi backlight with
acpi_backlight=vendor (iirc) kernel option or teach the X driver that
you want a different backlight driver in the xorg.conf (Option
"Backlight" "intel_backlight" should do the trick).
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)

[Tom St Denis]

Thanks Daniel so I'm taking back my bug report on the i915 and claiming this as a bug against the acpi_video stack.

What sort of information would the ACPI folk like from me to help diagnose this?

Here's a dmesg dump of all ACPI messages.

http://pastebin.com/b4XKe5Fk

Tom

----- Original Message -----
> From: "Daniel Vetter" <daniel.vetter@ffwll.ch>
> To: "Tom St Denis" <tstdenis@elliptictech.com>
> Cc: linux-kernel@vger.kernel.org, "intel-gfx" <intel-gfx@lists.freedesktop.org>, "dri-devel"
> <dri-devel@lists.freedesktop.org>
> Sent: Sunday, 2 December, 2012 9:42:39 AM
> Subject: Re: Brightness control fails between 3.6.8 and 3.7.0-rc7 (Intel 915/Dell Vostro 3560)
> 
> On Sun, Dec 2, 2012 at 2:49 PM, Tom St Denis
> <tstdenis@elliptictech.com> wrote:
> > Ok so on v3.7-rc1 [and I suspect up] I can manually control the
> > brightness by echoing to
> >
> > /sys/class/backlight/intel_backlight/brightness
> >
> > But I still can't use the buttons to control it (it only goes one
> > tick down from max and stops there).  I'm using GNOME3 from a
> > x86_64 unstable debian install [up to date with latest].
> >
> > I just noticed that under v3.7 I have a new directory
> > /sys/class/backlight/acpi_video1 which is what GNOME is actually
> > controlling.  I can't disable ACPI video control so is there a
> > workaround?
> 
> Hah, acpi registered a broken backlight driver, which overwrites the
> intel backlight - for once it's not i915.ko's fault ;-) For a
> workaround either disable the acpi backlight with
> acpi_backlight=vendor (iirc) kernel option or teach the X driver that
> you want a different backlight driver in the xorg.conf (Option
> "Backlight" "intel_backlight" should do the trick).
> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
>