video breaks asus-laptop display switching

video breaks asus-laptop display switching

[Andrei Gaponenko]

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

Re: video breaks asus-laptop display switching

[Zhang Rui]

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

Re: video breaks asus-laptop display switching

[Andrei Gaponenko]

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