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

DISCUSSION Tom St Denis 2 participants 7 messages Dec 1, 2012 – Dec 2, 2012 1 message not in the archive ACPI

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Tom St Denis

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#1 lore raw

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

author
#2 lore raw

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 -----

Quoted 36 lines

From: "Tom St Denis" <[email protected]>
To: [email protected]
Cc: "daniel vetter" <[email protected]>, [email protected]
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

#3 lore raw
Quoted 1 line · 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.

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

Signature · 3 lines
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
#4 lore raw

Including a bunch more lists to the cc.

Quoted 17 lines · Daniel Vetter
Quoted 1 line · 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.

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

Signature · 3 lines
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
author
#5 lore raw

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 -----

Quoted 39 lines

From: "Daniel Vetter" <[email protected]>
To: "Tom St Denis" <[email protected]>
Cc: [email protected], "intel-gfx" <[email protected]>, "dri-devel" <[email protected]>
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.

Quoted 15 lines · Daniel Vetter
Quoted 2 lines · 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.

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)?

Quoted 5 lines

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

#6 lore raw
Quoted 7 lines · 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?

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

Signature · 3 lines
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
author
#7 lore raw

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 -----

Quoted 35 lines

From: "Daniel Vetter" <[email protected]>
To: "Tom St Denis" <[email protected]>
Cc: [email protected], "intel-gfx" <[email protected]>, "dri-devel" <[email protected]>
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)

Quoted 5 lines · 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

Quoted 8 lines

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