Arch Linux

pshevtsov

Member

From: Novosibirsk, Russia

Registered: 2011-01-20

Posts: 52

[SUCCESS STORY] Arch, radeon and dual monitors

Hello!
Let me tell you my story of trial and error how I configured dual monitors with ATI graphics card on Arch Linux.

There are lots of articles, blog posts and forum threads in the iternets on this topic, but I hope that my story (and its solution) would also be useful for the community.

So, let the story begin!

First of all, I'd like to tell you about my hardware: graphics card and monitors.
My graphics card according to the output of

lspci | grep -i vga

is ATI Technologies Inc Mobility Radeon HD 3600 Series and my monitors are Acer AL1916W and Samsung SyncMaster 943NWX (both with resolution 1440x900)

I installed xf86-video-ati driver and configured it as it said in the perfect wiki article and plugged both monitors. But had no luck - both monitors had not have the right resolution neither in tty mode nor in graphics. Trying various snippets from the internets and having no luck either, I decided to try ATI Catalyst drivers.

Almost everything was quite good, I had configured my monitors in ATI Catalyst Control Center, but this solution brought me another new problem - the tty mode wasn't usable anymore, which I found unacceptable. Googling a lot I got that there is no way to make tty work with ATI Catalyst since I have to enable KMS for tty to work but have to disable KMS for Catalyst.

So, I had to get back to xf86-video-ati driver and try to configure X for my dual monitors to work.

I don't remember exactly where I've found the solution but after a set of trials and errors I got the following configuration file which I saved in /etc/X11/xorg.conf.d/10-monitor.conf:

Section "Device"
    Identifier      "ATI Technologies Inc Mobility Radeon HD 3600 Series"
    Driver         "radeon"

    # Using the name of the output defined by the video driver plus the identifier of a
    # monitor section, one associates a monitor section with an output by adding an
    # option to the Device section in the following format:
    # Option "Monitor-outputname" "monitor ID"

    Option          "monitor-DVI-0" "Acer"
    Option          "monitor-DVI-1" "Samsung"
EndSection

Section "Monitor"
    Identifier      "Acer"
EndSection

Section "Monitor"
    Identifier      "Samsung"
    Option "RightOf"  "Acer"
EndSection

Section "Screen"
    Identifier    "Default Screen"
    Device        "ATI Technologies Inc Mobility Radeon HD 3600 Series"
    Monitor       "Acer"
    DefaultDepth  24
    SubSection "Display"
        Depth         24
        Modes         "1440x900"
    EndSubSection
EndSection

But I also wasn't quite happy with the results. It turned that my right monitor (Samsung) still displayed the wrong resolution - 1024x768 instead of 1440x900. Even when I tried to force resolution with xrandr it was rejected. I googled more and found that I need to add new Modeline to my Monitor section. With the help of cvt utility I got the right line to put in my /etc/X11/xorg.conf.d/10-monitor.conf:

cvt 1440 900
# 1440x900 59.89 Hz (CVT 1.30MA) hsync: 55.93 kHz; pclk: 106.50 MHz
Modeline "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync

I added the Modeline to my /etc/X11/xorg.conf.d/10-monitor.conf and also added PreferredMode option. After that my configuration looks the following:

Section "Device"
    Identifier      "ATI Technologies Inc Mobility Radeon HD 3600 Series"
    Driver         "radeon"

    # Using the name of the output defined by the video driver plus the identifier of a
    # monitor section, one associates a monitor section with an output by adding an
    # option to the Device section in the following format:
    # Option "Monitor-outputname" "monitor ID"

    Option          "monitor-DVI-0" "Acer"
    Option          "monitor-DVI-1" "Samsung"
EndSection

Section "Monitor"
    Identifier      "Acer"
EndSection

Section "Monitor"
    Identifier      "Samsung"
    Modeline        "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync
    Option          "PreferredMode" "1440x900_60.00"
    Option "RightOf"  "Acer"
EndSection

Section "Screen"
    Identifier    "Default Screen"
    Device        "ATI Technologies Inc Mobility Radeon HD 3600 Series"
    Monitor       "Acer"
    DefaultDepth  24
    SubSection "Display"
        Depth         24
        Modes         "1440x900"
    EndSubSection
EndSection

Finally my both monitors worked perfectly in graphics mode, but there still was the issue with tty mode in which the same right monitor (Samsung) worked in wrong resolution.

Since I use GRUB2, I had to add video=1440x900 to GRUB_CMDLINE_LINUX_DEFAULT in my /etc/default/grub and update GRUB config with

sudo grub-mkconfig -o /boot/grub/grub.cfg

That's all. Hope that my story was if not useful but then interesting to read.

---

my Bitbucket | my AUR packages | my Dropbox referral link

llawwehttam

Member

From: United Kingdom

Registered: 2010-01-19

Posts: 181

Re: [SUCCESS STORY] Arch, radeon and dual monitors

Nice to see a success story with ATI. I switched to nvidia as I couldn't be bothered to put in the work to fix it and I prefer green over red XD.

ginoh

Member

Registered: 2011-05-18

Posts: 4

Re: [SUCCESS STORY] Arch, radeon and dual monitors

Tnx, saved me a lot of time!

nadman10

Member

From: Erie, PA

Registered: 2005-10-15

Posts: 200

Re: [SUCCESS STORY] Arch, radeon and dual monitors

Helped me too. I also have an AL1916W and it has been a thorn in my side. Thank you.