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Thread: [Howto] Set CRT monitor to >85Hz with drv-ati driver.

  1. #1
    Join Date
    Jun 2008
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    167

    Default [Howto] Set CRT monitor to >85Hz with drv-ati driver.

    Hello everybody!

    This is not a request for help, it's a howto. I have been puzzled by this problem for a long time, but now I found time to look into the issue.

    I have an old CRT monitor, but however it's quite good. It's a Philips 109P20:
    http://www.monitech.com.au/products/...ps/109p20.html
    It can do 800x600 @ 120Hz (maybe even more...), 1280x1024 @ 100Hz, 1600x1200 @ 85Hz.
    However Xorg (and now KMS) with the open driver never showed me the possibilty to set refreshes higher than 85Hz.
    Only fglrx found 100Hz refreshes...

    Now I found a simple way to add the same modelines as Windows to the xorg.conf without breaking everything. A good guide is:
    http://www.x.org/wiki/FAQVideoModes#...39732ee868e0d2
    Get the modes with PowerStrip as described, and if you have "," as decimal separator remember to change "," to ".":
    http://ubuntuforums.org/showthread.php?t=451569

    In the "Monitor" section add Option "DPMS" to add all the autodetected modes, and then you can add custom Modelines. If you name the modeline as the resolution you'll get the refresh listed in the original resolution.

    To make you an example, this was the output of xrandr before:
    Code:
    Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 3840 x 1920
    VGA-0 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 355mm x 265mm
       1280x1024      85.0*    75.0     60.0
       1920x1440      60.0
       1856x1392      60.0
       1792x1344      75.0     60.0     60.0
       1600x1200      85.0     85.0     75.0     70.0     65.0     60.0
       1400x1050      74.8     60.0
       1280x960       85.0     60.0
       1024x768       85.0     75.0     70.1     60.0     43.5
       832x624        74.6
       800x600        85.1     85.1     72.2     75.0     60.3     56.2
       640x480        85.0     75.0     72.8     75.0     66.7     59.9
       720x400        87.8     85.0     70.1
       640x400        85.1
       640x350        85.1
    DVI-0 disconnected (normal left inverted right x axis y axis)
    S-video disconnected (normal left inverted right x axis y axis)
    and this is now that I added 1280@100, 1152@100 and 1024@100:
    Code:
    Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 3840 x 1920
    VGA-0 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 355mm x 265mm
       1280x1024     100.2*+   85.0     75.0     60.0
       1920x1440      60.0
       1856x1392      60.0
       1792x1344      75.0     60.0     60.0
       1600x1200      85.0     85.0     75.0     70.0     65.0     60.0
       1400x1050      74.8     60.0
       1280x960       85.0     60.0
       1152x864      100.0     75.0
       1024x768      100.1     85.0     75.0     70.1     60.0     43.5
       832x624        74.6
       800x600        85.1     85.1     72.2     75.0     60.3     56.2
       640x480        85.0     75.0     72.8     75.0     66.7     59.9
       720x400        87.8     85.0     70.1
       640x400        85.1
       640x350        85.1
    DVI-0 disconnected (normal left inverted right x axis y axis)
    S-video disconnected (normal left inverted right x axis y axis)
    What I added to my xorg.conf is this Monitor section:
    Code:
    Section "Monitor"
            Identifier      "Philips 109P20"
            VendorName      "Philips"
            ModelName       "109P20"
            Option          "DPMS"
            Modeline        "1280x1024" 191.250 1280 1384 1528 1760 1024 1025 1028 1085 -hsync +vsync
            Modeline        "1152x864" 143.438 1152 1240 1368 1568 864 865 868 915 -hsync +vsync
            Modeline        "1024x768" 113.400 1024 1104 1216 1392 768 769 772 814 -hsync +vsync
    EndSection
    Hope this helps somebody!

  2. #2
    Join Date
    Jun 2008
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    167

    Default

    BTW, a little question to eventual developers that read this: is there a possibility that this can be fixed in KMS or in drv-ati at some point or is it unlikely?

    If you need more infos I can file a bug report with the Xorg.0.log / dmesg contents.
    A copy of my Xorg.0.log can be found here:
    https://bugzilla.redhat.com/attachment.cgi?id=314882
    https://bugzilla.redhat.com/show_bug.cgi?id=459907

  3. #3
    Join Date
    Dec 2007
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    2,395

    Default

    This isn't really a bug. The xserver adds the modes that are in the edid from the monitor along with certain common modes that are within the sync ranges listed in the edid (assuming the edid indicates the monitor supports continuous sync ranges). Beyond that, you have to add modes manually; there's no way to know what modes are safe to use with the monitor.

  4. #4
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    It would be more logical to add 1280x960 instead of 1280x1024 as the last one is purely for TFT screens with 5:4 and not 4:3 aspect.

  5. #5
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    Thanks agd5f. Infact this is my monitor-edid output:
    Code:
    [root@localhost ~]# monitor-edid -v
    probing EDID using VBE (port 0)    
      vbe: int 10h points to c000:1ef6: fb fc 80 fc a0 0f 84 17
    VBE version: 2.0, oem version = 1.0                        
    Memory: 131072k                                            
    OEM name: ATI R300                                         
    Vendor name: ATI Technologies Inc.                         
    Product name: R300                                         
    Product revision: 01.00                                    
    parsing EDID from vbe                                      
    Name: PHILIPS 109P2                                        
    EISA ID: PHL0005                                           
    Screen size: 35.5 cm x 26.5 cm (17.44 inches, aspect ratio 4/3 = 1.34)
    Gamma: 2.67                                                           
    Analog signal
    Standard resolution: 640x480 @ 60 Hz (established timing)
    Standard resolution: 640x480 @ 67 Hz (established timing)
    Standard resolution: 640x480 @ 72 Hz (established timing)
    Standard resolution: 640x480 @ 75 Hz (established timing)
    Standard resolution: 720x400 @ 70 Hz (established timing)
    Standard resolution: 720x400 @ 88 Hz (established timing)
    Standard resolution: 800x600 @ 60 Hz (established timing)
    Standard resolution: 800x600 @ 72 Hz (established timing)
    Standard resolution: 800x600 @ 75 Hz (established timing)
    Standard resolution: 832x624 @ 75 Hz (established timing)
    Standard resolution: 1024x768 @ 60 Hz (established timing)
    Standard resolution: 1024x768 @ 70 Hz (established timing)
    Standard resolution: 1024x768 @ 75 Hz (established timing)
    Standard resolution: 1280x1024 @ 75 Hz (established timing)
    Standard resolution: 1920x1440 @ 60 Hz, ratio 4/3
    Standard resolution: 1792x1344 @ 60 Hz, ratio 4/3
    Standard resolution: 1600x1200 @ 75 Hz, ratio 4/3
    Standard resolution: 1280x1024 @ 85 Hz, ratio 5/4 (!)
    Standard resolution: 1280x1024 @ 60 Hz, ratio 5/4 (!)
    Standard resolution: 1024x768 @ 85 Hz, ratio 4/3
    Standard resolution: 800x600 @ 85 Hz, ratio 4/3
    Standard resolution: 640x480 @ 85 Hz, ratio 4/3
    Max video bandwidth: 260 MHz
    
            HorizSync 30-111
            VertRefresh 50-160
    
            # Monitor preferred modeline (85.0 Hz vsync, 106.2 kHz hsync, ratio 4/3)
            ModeLine "1600x1200" 229.5 1600 1664 1856 2160 1200 1201 1204 1250 -hsync -vsync
    @Kano:
    Philips reccomends 1280x1024...
    http://www.p4c.philips.com/files/1/1...0c_pss_eng.pdf
    I have no real problem with 5:4 ratio, so that's ok...
    I'll try 1152x864 or, as you suggest, 1280x960.

  6. #6
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    Anybody using 1280x1024 on CRT has strange eyes - some are so used to it that they do not even see that a circle or quad is not looking correctly.

  7. #7
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    Quote Originally Posted by Kano View Post
    Anybody using 1280x1024 on CRT has strange eyes - some are so used to it that they do not even see that a circle or quad is not looking correctly.
    You're right, but working mostly with text you don't really pay much attention. But now you make me really wonder why so many CRT used 1280x1024 and not 960. I've always wondered why such a strange resolution is so widespread...

  8. #8
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    1280x1024 is vesa standard, 1280x960 is not.

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