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video breaks asus-laptop display switching

 

 

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andrei.gaponenko at cern

Dec 21, 2007, 2:36 PM

Post #1 of 3 (911 views)
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video breaks asus-laptop display switching

Hi,

With 2.6.23 or newer (including 2.6.24-rc6) kernels, writing to the
/sys/devices/platform/asus-laptop/display file does not do anything:

Cold boot to single user, then connect an external monitor

# cat /sys/devices/platform/asus-laptop/display
1

OK, only the built in LCD is enabled. Try to enable
the external monitor as well:

# echo 3 > /sys/devices/platform/asus-laptop/display

still no image on the external.

# cat /sys/devices/platform/asus-laptop/display
1

Still "1", not the "3" we wrote. On the other hand if I boot with an
external monitor attached, the "display" file always contains 3, even
after writing 1 there, and there is image on both monitors.

In 2.6.22 I had to load asus-laptop by hand, but then display
switching worked nicely.

I've noticed that if I do

# rmmod video

display switching starts working again with the newer kernels.
The "video" module was auto-loaded on my system in 2.6.22, but
did not cause the conflict.

This is an ASUS Z71V based notebook (detected as M7V).

Regards,
Andrei

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rui.zhang at intel

Dec 21, 2007, 11:53 PM

Post #2 of 3 (816 views)
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Re: video breaks asus-laptop display switching [In reply to]

On Sat, 2007-12-22 at 06:36 +0800, Andrei Gaponenko wrote:
>
> Hi,
>
> With 2.6.23 or newer (including 2.6.24-rc6) kernels, writing to the
> /sys/devices/platform/asus-laptop/display file does not do anything:
>
> Cold boot to single user, then connect an external monitor
>
> # cat /sys/devices/platform/asus-laptop/display
> 1
>
> OK, only the built in LCD is enabled. Try to enable
> the external monitor as well:
>
> # echo 3 > /sys/devices/platform/asus-laptop/display
>
> still no image on the external.
>
> # cat /sys/devices/platform/asus-laptop/display
> 1
>
> Still "1", not the "3" we wrote. On the other hand if I boot with an
> external monitor attached, the "display" file always contains 3, even
> after writing 1 there, and there is image on both monitors.
>
> In 2.6.22 I had to load asus-laptop by hand, but then display
> switching worked nicely.
>
> I've noticed that if I do
>
> # rmmod video
>
> display switching starts working again with the newer kernels.
> The "video" module was auto-loaded on my system in 2.6.22, but
> did not cause the conflict.
hmm, please "echo 1 > /proc/acpi/video/xxx/DOS" in 2.6.23 and see
if there is any difference.

Thansk,
Rui


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andrei.gaponenko at cern

Dec 22, 2007, 12:21 AM

Post #3 of 3 (805 views)
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Re: video breaks asus-laptop display switching [In reply to]

On Sat, 22 Dec 2007, Zhang Rui wrote:

> On Sat, 2007-12-22 at 06:36 +0800, Andrei Gaponenko wrote:
>>
>> With 2.6.23 or newer (including 2.6.24-rc6) kernels, writing to the
>> /sys/devices/platform/asus-laptop/display file does not do anything:
>> ...
>>
> hmm, please "echo 1 > /proc/acpi/video/xxx/DOS" in 2.6.23 and see
> if there is any difference.

ls /proc/acpi/video/
shows two identically named directories "VGA" - is this normal??

Anyway,

# cat VGA/DOS
DOS setting: <1>

# echo 3 > VGA/DOS
# cat VGA/DOS
DOS setting: <3>

but no image on external. Now

# rmmod video
# echo 3 > /sys/devices/platform/asus-laptop/display

Got image on external

# modprobe video
# cat VGA/DOS
DOS setting: <0>

I can write 1 or 3 to DOS and read it back, but it has no effect (image on
external turned on while video module was removed does not go away).

Please Cc: me on replies - forgot to mention this in the initial posting.

Thanks!
Andrei
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