backlight regression on ASUS F6S: inverted brightness control

backlight regression on ASUS F6S: inverted brightness control

[Kel Modderman]

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Hi,

After booting Linux 2.6.28 the backlight control actions have now reversed,
ie: attempting to make backlight brighter makes it dimmer and vice versa.

The recent backlight changes (video vs. vendor) seem to have the result of
allowing the ASUS F6S backlight hardware be driven via the acpi/video driver
rather than the vendor/asus_laptop driver as per printk:

asus-laptop: Brightness ignored, must be controlled by ACPI video driver

Linux < 2.6.28
--------------
# cat /sys/class/backlight/asus-laptop/max_brightness
15

# Makes backlight brightest
# echo 15 > /sys/class/backlight/asus-laptop/brightness

# Makes backlight dimmest
# echo 0 > /sys/class/backlight/asus-laptop/brightness

Linux = 2.6.28
--------------
# cat /sys/class/backlight/acpi_video0/max_brightness
13

# Makes backlight brightest
# echo 0 > /sys/class/backlight/acpi_video0/brightness

# Makes backlight dimmest
# echo 13 > /sys/class/backlight/acpi_video0/brightness


A search for "linux 2.6.28 backlight" led to an Ubuntu bug report [1] which
describes an ASUS notebook user with the same situation.

[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/305935

Is it possible to have the ACPI video driver to behave correctly on this
hardware?

I'd like to provide any further required information. I've attached a bzip
tarball containing:
  /sys/devices/platform/asus-laptop/infos
  /proc/acpi/dsdt
  dmesg output
  dmidecode output

Thanks, Kel.

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Re: backlight regression on ASUS F6S: inverted brightness control

[Zhang Rui]

hi,

This is a duplicate of bug
http://bugzilla.kernel.org/show_bug.cgi?id=12302
please try the patch at
http://bugzilla.kernel.org/show_bug.cgi?id=12037#c5

thanks,
rui

On Sun, 2008-12-28 at 04:11 +0800, Kel Modderman wrote:
> Hi,
> 
> After booting Linux 2.6.28 the backlight control actions have now reversed,
> ie: attempting to make backlight brighter makes it dimmer and vice versa.
> 
> The recent backlight changes (video vs. vendor) seem to have the result of
> allowing the ASUS F6S backlight hardware be driven via the acpi/video driver
> rather than the vendor/asus_laptop driver as per printk:
> 
> asus-laptop: Brightness ignored, must be controlled by ACPI video driver
> 
> Linux < 2.6.28
> --------------
> # cat /sys/class/backlight/asus-laptop/max_brightness
> 15
> 
> # Makes backlight brightest
> # echo 15 > /sys/class/backlight/asus-laptop/brightness
> 
> # Makes backlight dimmest
> # echo 0 > /sys/class/backlight/asus-laptop/brightness
> 
> Linux = 2.6.28
> --------------
> # cat /sys/class/backlight/acpi_video0/max_brightness
> 13
> 
> # Makes backlight brightest
> # echo 0 > /sys/class/backlight/acpi_video0/brightness
> 
> # Makes backlight dimmest
> # echo 13 > /sys/class/backlight/acpi_video0/brightness
> 
> 
> A search for "linux 2.6.28 backlight" led to an Ubuntu bug report [1] which
> describes an ASUS notebook user with the same situation.
> 
> [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/305935
> 
> Is it possible to have the ACPI video driver to behave correctly on this
> hardware?
> 
> I'd like to provide any further required information. I've attached a bzip
> tarball containing:
>   /sys/devices/platform/asus-laptop/infos
>   /proc/acpi/dsdt
>   dmesg output
>   dmidecode output
> 
> Thanks, Kel.

Re: backlight regression on ASUS F6S: inverted brightness control

[Kel Modderman]

On Monday 29 December 2008 11:07:32 Zhang Rui wrote:
> hi,
> 
> This is a duplicate of bug
> http://bugzilla.kernel.org/show_bug.cgi?id=12302
> please try the patch at
> http://bugzilla.kernel.org/show_bug.cgi?id=12037#c5

When patch is applied backlight control returned to normality.

Thanks, Kel.

Re: backlight regression on ASUS F6S: inverted brightness control

[Zhang Rui]

On Mon, 2008-12-29 at 16:39 +0800, Kel Modderman wrote:
> On Monday 29 December 2008 11:07:32 Zhang Rui wrote:
> > hi,
> > 
> > This is a duplicate of bug
> > http://bugzilla.kernel.org/show_bug.cgi?id=12302
> > please try the patch at
> > http://bugzilla.kernel.org/show_bug.cgi?id=12037#c5
> 
> When patch is applied backlight control returned to normality.
> 
please attach the output of "grep . /proc/acpi/video/*/*/*" both before
and after applying this patch.

thanks,
rui

Re: backlight regression on ASUS F6S: inverted brightness control

[Kel Modderman]

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On Tuesday 30 December 2008 11:37:47 Zhang Rui wrote:
> On Mon, 2008-12-29 at 16:39 +0800, Kel Modderman wrote:
> > On Monday 29 December 2008 11:07:32 Zhang Rui wrote:
> > > hi,
> > > 
> > > This is a duplicate of bug
> > > http://bugzilla.kernel.org/show_bug.cgi?id=12302
> > > please try the patch at
> > > http://bugzilla.kernel.org/show_bug.cgi?id=12037#c5
> > 
> > When patch is applied backlight control returned to normality.
> > 
> please attach the output of "grep . /proc/acpi/video/*/*/*" both before
> and after applying this patch.

Attached.

Thanks, Kel

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/proc/acpi/video/VGA/CRTD/brightness:<not supported>
/proc/acpi/video/VGA/CRTD/EDID:<not supported>
/proc/acpi/video/VGA/CRTD/info:device_id:    0x0100
/proc/acpi/video/VGA/CRTD/info:type:         UNKNOWN
/proc/acpi/video/VGA/CRTD/info:known by bios: no
/proc/acpi/video/VGA/CRTD/state:state:     0x1d
/proc/acpi/video/VGA/CRTD/state:query:     0x00
/proc/acpi/video/VGA/DVID/brightness:<not supported>
/proc/acpi/video/VGA/DVID/EDID:<not supported>
/proc/acpi/video/VGA/DVID/info:device_id:    0x0120
/proc/acpi/video/VGA/DVID/info:type:         UNKNOWN
/proc/acpi/video/VGA/DVID/info:known by bios: no
/proc/acpi/video/VGA/DVID/state:state:     0x1d
/proc/acpi/video/VGA/DVID/state:query:     0x00
/proc/acpi/video/VGA/LCDD/brightness:levels:  15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
/proc/acpi/video/VGA/LCDD/brightness:current: 0
/proc/acpi/video/VGA/LCDD/EDID:<not supported>
/proc/acpi/video/VGA/LCDD/info:device_id:    0x0110
/proc/acpi/video/VGA/LCDD/info:type:         UNKNOWN
/proc/acpi/video/VGA/LCDD/info:known by bios: no
/proc/acpi/video/VGA/LCDD/state:state:     0x1f
/proc/acpi/video/VGA/LCDD/state:query:     0x01

[-- Attachment #3: after --]
[-- Type: text/plain, Size: 1130 bytes --]

/proc/acpi/video/VGA/CRTD/brightness:<not supported>
/proc/acpi/video/VGA/CRTD/EDID:<not supported>
/proc/acpi/video/VGA/CRTD/info:device_id:    0x0100
/proc/acpi/video/VGA/CRTD/info:type:         UNKNOWN
/proc/acpi/video/VGA/CRTD/info:known by bios: no
/proc/acpi/video/VGA/CRTD/state:state:     0x1d
/proc/acpi/video/VGA/CRTD/state:query:     0x00
/proc/acpi/video/VGA/DVID/brightness:<not supported>
/proc/acpi/video/VGA/DVID/EDID:<not supported>
/proc/acpi/video/VGA/DVID/info:device_id:    0x0120
/proc/acpi/video/VGA/DVID/info:type:         UNKNOWN
/proc/acpi/video/VGA/DVID/info:known by bios: no
/proc/acpi/video/VGA/DVID/state:state:     0x1d
/proc/acpi/video/VGA/DVID/state:query:     0x00
/proc/acpi/video/VGA/LCDD/brightness:levels:  15 14 0 1 2 3 4 5 6 7 8 9 10 11 12 13
/proc/acpi/video/VGA/LCDD/brightness:current: 13
/proc/acpi/video/VGA/LCDD/EDID:<not supported>
/proc/acpi/video/VGA/LCDD/info:device_id:    0x0110
/proc/acpi/video/VGA/LCDD/info:type:         UNKNOWN
/proc/acpi/video/VGA/LCDD/info:known by bios: no
/proc/acpi/video/VGA/LCDD/state:state:     0x1f
/proc/acpi/video/VGA/LCDD/state:query:     0x01

Re: backlight regression on ASUS F6S: inverted brightness control

[Zhang Rui]

the ACPI video backlight I/F on your laptop is broken.
could you please boot with acpi_backlight=vendor and see if it works at
before?

BTW: please attach the output of "grep . /proc/acpi/video/*/*/*" in 
1. 2.6.28 kenrel & boot with "acpi_backlight=vendor"
2. an earlier working kernel, say 2.6.26.

thanks,
rui


On Wed, 2008-12-31 at 00:02 +0800, Kel Modderman wrote:
> On Tuesday 30 December 2008 11:37:47 Zhang Rui wrote:
> > On Mon, 2008-12-29 at 16:39 +0800, Kel Modderman wrote:
> > > On Monday 29 December 2008 11:07:32 Zhang Rui wrote:
> > > > hi,
> > > > 
> > > > This is a duplicate of bug
> > > > http://bugzilla.kernel.org/show_bug.cgi?id=12302
> > > > please try the patch at
> > > > http://bugzilla.kernel.org/show_bug.cgi?id=12037#c5
> > > 
> > > When patch is applied backlight control returned to normality.
> > > 
> > please attach the output of "grep . /proc/acpi/video/*/*/*" both before
> > and after applying this patch.
> 
> Attached.
> 
> Thanks, Kel

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Re: backlight regression on ASUS F6S: inverted brightness control

[Zhang Rui]

Hi, thomas,

we got a couple of regressions caused by the acpi video detect patch
set.
IMO, the reason is that they have buggy ACPI video extension
implemented. and these laptops used to control the backlight via
platform drivers.

you can refer to this thread or the bug:
http://bugzilla.kernel.org/show_bug.cgi?id=12037
http://bugzilla.kernel.org/show_bug.cgi?id=12235
http://bugzilla.kernel.org/show_bug.cgi?id=12249
http://bugzilla.kernel.org/show_bug.cgi?id=12302

I have fixed one by overriding the DSDT.
the source code of the customized DSDT can be found at
http://bugzilla.kernel.org/show_bug.cgi?id=12249#c32

so IMO, acpi_video_backlight_support should be able to verify if BIOS
offers buggy ACPI backlight control methods and returns false  in this
case. but then we need to move a lot of ACPI video code
(acpi_video_init_brightness) to video_detect.c, which doesn't sound
quite good. what do you think?

thanks,
rui

On Wed, 2008-12-31 at 11:33 +0800, Zhang Rui wrote:
> the ACPI video backlight I/F on your laptop is broken.
> could you please boot with acpi_backlight=vendor and see if it works at
> before?
> 
> BTW: please attach the output of "grep . /proc/acpi/video/*/*/*" in 
> 1. 2.6.28 kenrel & boot with "acpi_backlight=vendor"
> 2. an earlier working kernel, say 2.6.26.
> 
> thanks,
> rui
> 
> 
> On Wed, 2008-12-31 at 00:02 +0800, Kel Modderman wrote:
> > On Tuesday 30 December 2008 11:37:47 Zhang Rui wrote:
> > > On Mon, 2008-12-29 at 16:39 +0800, Kel Modderman wrote:
> > > > On Monday 29 December 2008 11:07:32 Zhang Rui wrote:
> > > > > hi,
> > > > > 
> > > > > This is a duplicate of bug
> > > > > http://bugzilla.kernel.org/show_bug.cgi?id=12302
> > > > > please try the patch at
> > > > > http://bugzilla.kernel.org/show_bug.cgi?id=12037#c5
> > > > 
> > > > When patch is applied backlight control returned to normality.
> > > > 
> > > please attach the output of "grep . /proc/acpi/video/*/*/*" both before
> > > and after applying this patch.
> > 
> > Attached.
> > 
> > Thanks, Kel
> 
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Re: backlight regression on ASUS F6S: inverted brightness control

[Matthew Garrett]

On Wed, Dec 31, 2008 at 11:33:28AM +0800, Zhang Rui wrote:
> the ACPI video backlight I/F on your laptop is broken.

It looks pretty easy for us to be able to fix up the lists in this case. 
If it's present on several systems then we probably ought to.

Re: backlight regression on ASUS F6S: inverted brightness control

[Kel Modderman]

On Wednesday 31 December 2008 13:33:28 Zhang Rui wrote:
> the ACPI video backlight I/F on your laptop is broken.
> could you please boot with acpi_backlight=vendor and see if it works at
> before?
> 
> BTW: please attach the output of "grep . /proc/acpi/video/*/*/*" in 
> 1. 2.6.28 kenrel & boot with "acpi_backlight=vendor"

/proc/acpi/video/VGA/CRTD/brightness:<not supported>
/proc/acpi/video/VGA/CRTD/EDID:<not supported>
/proc/acpi/video/VGA/CRTD/info:device_id:    0x0100
/proc/acpi/video/VGA/CRTD/info:type:         UNKNOWN
/proc/acpi/video/VGA/CRTD/info:known by bios: no
/proc/acpi/video/VGA/CRTD/state:state:     0x1d
/proc/acpi/video/VGA/CRTD/state:query:     0x00
/proc/acpi/video/VGA/DVID/brightness:<not supported>
/proc/acpi/video/VGA/DVID/EDID:<not supported>
/proc/acpi/video/VGA/DVID/info:device_id:    0x0120
/proc/acpi/video/VGA/DVID/info:type:         UNKNOWN
/proc/acpi/video/VGA/DVID/info:known by bios: no
/proc/acpi/video/VGA/DVID/state:state:     0x1d
/proc/acpi/video/VGA/DVID/state:query:     0x00
/proc/acpi/video/VGA/LCDD/brightness:<not supported>
/proc/acpi/video/VGA/LCDD/EDID:<not supported>
/proc/acpi/video/VGA/LCDD/info:device_id:    0x0110
/proc/acpi/video/VGA/LCDD/info:type:         UNKNOWN
/proc/acpi/video/VGA/LCDD/info:known by bios: no
/proc/acpi/video/VGA/LCDD/state:state:     0x1f
/proc/acpi/video/VGA/LCDD/state:query:     0x01

> 2. an earlier working kernel, say 2.6.26.

/proc/acpi/video/VGA/CRTD/brightness:<not supported>
/proc/acpi/video/VGA/CRTD/EDID:<not supported>
/proc/acpi/video/VGA/CRTD/info:device_id:    0x0100
/proc/acpi/video/VGA/CRTD/info:type:         UNKNOWN
/proc/acpi/video/VGA/CRTD/info:known by bios: no
/proc/acpi/video/VGA/CRTD/state:state:     0x1d
/proc/acpi/video/VGA/CRTD/state:query:     0x00
/proc/acpi/video/VGA/DVID/brightness:<not supported>
/proc/acpi/video/VGA/DVID/EDID:<not supported>
/proc/acpi/video/VGA/DVID/info:device_id:    0x0120
/proc/acpi/video/VGA/DVID/info:type:         UNKNOWN
/proc/acpi/video/VGA/DVID/info:known by bios: no
/proc/acpi/video/VGA/DVID/state:state:     0x1d
/proc/acpi/video/VGA/DVID/state:query:     0x00
/proc/acpi/video/VGA/LCDD/brightness:levels:  15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
/proc/acpi/video/VGA/LCDD/brightness:current: 13
/proc/acpi/video/VGA/LCDD/EDID:<not supported>
/proc/acpi/video/VGA/LCDD/info:device_id:    0x0110
/proc/acpi/video/VGA/LCDD/info:type:         UNKNOWN
/proc/acpi/video/VGA/LCDD/info:known by bios: no
/proc/acpi/video/VGA/LCDD/state:state:     0x1f
/proc/acpi/video/VGA/LCDD/state:query:     0x01

Thanks, Kel.
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