Displayconfig tool based on Guidance

Comment 3 for bug 150426

Loye Young (loyeyoung) wrote :

My company sells the Acer AL1917W, which I believe is the same as the AL1916W but with speakers.

I haven't read the code for displayconfig-gtk, so I can't give you code changes. However, I can give you the necessary changes to /etc/X11/xorg.conf for the Acer 1917W, and then give you a step-by-step to figure it out for other monitors. When you get the answer for your monitor, post it here so the developers can have the benefit of the specifics.

<strong>/etc/X11/xorg.conf settings for the Acer 1917W</strong>

Delete the "Monitor" section and replace with:
Section "Monitor"
 # Block type: 2:0 3:fd
 # Block type: 2:0 3:ff
 # Block type: 2:0 3:fc
 Identifier "AL1917W"
 VendorName "ACR"
 ModelName "AL1917W"
 # Block type: 2:0 3:fd
 HorizSync 31-84
 VertRefresh 56-76
 # Max dot clock (video bandwidth) 140 MHz
 # Block type: 2:0 3:ff
 # Block type: 2:0 3:fc
 # DPMS capabilities: Active off:yes Suspend:yes Standby:yes

 Mode "1440x900" # vfreq 60.070Hz, hfreq 55.625kHz
  DotClock 89.000000
  HTimings 1440 1488 1520 1600
  VTimings 900 903 909 926
  Flags "+HSync" "+VSync"
 # Block type: 2:0 3:fd
 # Block type: 2:0 3:ff
 # Block type: 2:0 3:fc

In your Screens section , change the Monitor line to:
 Monitor "AL1917W"[/code]
If the Screens section has a Display subsection, remove that subsection.

Add the following subsection to the Screens section:
 SubSection "Display"
  Modes "1440x900"

<strong>General solution to finding the proper settings for any monitor</strong>

I don't know the settings for your monitor, but I can tell you how to figure it out. I'll first give you the steps and then show you the specifics.

Here are the steps:
Go to a terminal and become root.
Install some packages.
Test drive read-edid to ensure that the monitor and graphics card can report reliable results.
Update your xorg.conf file using read-edid.
Manually conform xorg.conf to your new settings.

Here are the specifics. Don't type the # or anything that follows on the same line:
sudo -s
# Type your password. You won't see anything change while you are typing. Just type on faith.
# Now you are root.

aptitude install read-edid fbset
# aptitude does its usual thing, possibly asking you questions that you should answer.

get-edid | parse-edid | less
# Read the output. It will tell you if you should not trust the answer.
# If it says you shouldn't, stop and find another solution.

# If all is well . . .
get-edid | parse-edid >> /etc/X11/xorg.conf

nano /etc/X11/xorg.conf

At the bottom of the file is your new Monitor section.
Make note of the Identifier and Mode settings. You will need
them for what follows. My Identifier is "AL1917W", and my
Mode is "1440x900" so they are what I will use. In your Screens
section, change the Monitor line to the Identifier code for
your monitor, to wit:
    Monitor "AL1917W"

If the Screens section has a SubSection called Display, remove
the subsection. Add the following subsection to the Screens section:
    SubSection "Display"
        Modes "1440x900"

Save the file and restart X (i.e., log out and then hold down Ctrl-Alt-Backspace all at the same time).

You may have to experiment with the DefaultDepth setting. If you graphics card has enough memory, 24 will give you the best color. However, keeping 1440 x 900 (1,296,000) pixels lit up at 24 bits per pixel, 60 times a second is a lot of work for a graphics card. If you don't get good results at 24 bit depth, try backing it off to 16 and see what you get. (I even have in one of my machines an old ATI Mach64 card with only 4 MB of memory, so I have to reduce the depth to 8 to get it to work.)