[ltp] External video on T61
Dmitry E. Mikhailov
linux-thinkpad@linux-thinkpad.org
Tue, 20 May 2008 11:03:25 +0600
Hi,
The video output is controlled by thinkpad_acpi module. First check out if
it's in memory:
[tn@ibm ~]$ /sbin/lsmod|grep thinkpad_acpi
thinkpad_acpi 43704 0
If it is not in memory, then load it (you need superuser rights).
/sbin/modprobe thinkpad_acpi
Then check this out:
[tn@ibm ~]$ cd /proc/acpi/ibm/
[tn@ibm ibm]$ ls
beep bluetooth cmos driver fan hotkey led light thermal video volume
Video output is controlled by '/proc/acpi/ibm/video' file:
[tn@ibm ibm]$ cat video
status: supported
lcd: enabled
crt: disabled
dvi: disabled
auto: enabled
commands: lcd_enable, lcd_disable
commands: crt_enable, crt_disable
commands: dvi_enable, dvi_disable
commands: auto_enable, auto_disable
commands: video_switch, expand_toggle
Thinkpad_acpi documentation
($kernel_source_path$/Documentation/thinkpad_acpi.txt) says:
<QUOTE>
Video output control -- /proc/acpi/ibm/video
--------------------------------------------
This feature allows control over the devices used for video output -
LCD, CRT or DVI (if available). The following commands are available:
echo lcd_enable > /proc/acpi/ibm/video
echo lcd_disable > /proc/acpi/ibm/video
echo crt_enable > /proc/acpi/ibm/video
echo crt_disable > /proc/acpi/ibm/video
echo dvi_enable > /proc/acpi/ibm/video
echo dvi_disable > /proc/acpi/ibm/video
echo auto_enable > /proc/acpi/ibm/video
echo auto_disable > /proc/acpi/ibm/video
echo expand_toggle > /proc/acpi/ibm/video
echo video_switch > /proc/acpi/ibm/video
Each video output device can be enabled or disabled individually.
Reading /proc/acpi/ibm/video shows the status of each device.
Automatic video switching can be enabled or disabled. When automatic
video switching is enabled, certain events (e.g. opening the lid,
docking or undocking) cause the video output device to change
automatically. While this can be useful, it also causes flickering
and, on the X40, video corruption. By disabling automatic switching,
the flickering or video corruption can be avoided.
The video_switch command cycles through the available video outputs
(it simulates the behavior of Fn-F7).
Video expansion can be toggled through this feature. This controls
whether the display is expanded to fill the entire LCD screen when a
mode with less than full resolution is used. Note that the current
video expansion status cannot be determined through this feature.
Note that on many models (particularly those using Radeon graphics
chips) the X driver configures the video card in a way which prevents
Fn-F7 from working. This also disables the video output switching
features of this driver, as it uses the same ACPI methods as
Fn-F7. Video switching on the console should still work.
UPDATE: There's now a patch for the X.org Radeon driver which
addresses this issue. Some people are reporting success with the patch
while others are still having problems. For more information:
https://bugs.freedesktop.org/show_bug.cgi?id=2000
</QUOTE>
BTW, it's worth reading this document if you'd like to fine-tune your
Thinkpad.
If you activated the manual control over all the Thinkpad's hot keys, you
won't get Fn-F7 working automatically. Write a script for ACPId to do this.
And IMHO automatic detection does not always work reliably.
Best regards, Dmitry
> Dear John,
>
> Using a T42, a T61, and an X61s in a college classroom with a data
> projector of some standard brand, I had it work reliably by doing two
> things after connecting the computer to the external monitor (data
> projector) cable: 1) turn on the projector and tell it to expect an rgb
> signal and 2) boot or reboot my computer. For some reason, the computer
> can't see the projector or the projector can't see the computer except that
> way. My other thinkpad buttons mostly work as they should, but with a
> running computer hot-plugged into a projector, running or otherwise, the
> Fn-F7 button machs nichs. It's a pain, but that's how it was.
>
> The above was true for Gutsy on the T42 and the T61 and for Hardy on the
> T61 and X61s.
>
> Best wishes,
> Tony
>
> On Mon, May 19, 2008 at 5:22 PM, John Jason Jordan <johnxj@comcast.net>
>
> wrote:
> > I have a T61 with Hardy x86_64, using nVidia driver and a laptop screen
> > resolution of 1680 x 1050. All is well.
> >
> > However, for the first time ever I need to do a presentation in a
> > classroom. The classroom is equipped with audiovisual equipment,
> > including a Windows XP computer. However, I am having a hell of a time
> > getting OpenOffice on Windows to play the presentation that I created
> > in OpenOffice on my own computer. At this point it seems preferable to
> > use my T61.
> >
> > The equipment in the classroom provides for input from a laptop
> > (standard D9 connector). I connected my computer to the classroom
> > equipment, but it cannot see a signal. Then I went to the Audiovisual
> > Help office at the university and we tried to connect my laptop. The
> > people there are knowledgeable about various computers and how to get
> > them to send video signal out, but we could not get it to work.
> >
> > One of the things the person in the AV office tried was Fn+F7, which he
> > said normally toggles the external video on and off. On my T61 it did
> > nothing.
> >
> > I know zero about this matter. Can someone offer me some suggestions?
> > --
> > The linux-thinkpad mailing list home page is at:
> > http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad