Cannot enable proper screen resolution

dotancohen · 05-09-2007, 12:47 PM

I cannot enable 1680x1050 resolution on my Dell Inspiron E1505/6400 laptop. Although I have properly configured xorg.conf, neither Gnome nor KDE give me the option to choose 1680x1050.

Code:

[root@localhost ~]# cat /etc/X11/xorg.conf
# Xorg configuration created by system-config-display

Section "ServerLayout"
        Identifier     "single head configuration"
        Screen      0  "Screen0" 0 0
        InputDevice    "Keyboard0" "CoreKeyboard"
        InputDevice    "Synaptics" "CorePointer"
EndSection

Section "InputDevice"
        Identifier  "Keyboard0"
        Driver      "kbd"
        Option      "XkbModel" "pc105"
        Option      "XkbLayout" "us"
EndSection

Section "InputDevice"
        Identifier  "Synaptics"
        Driver      "synaptics"
        Option      "Device" "/dev/input/mice"
        Option      "Protocol" "auto-dev"
        Option      "Emulate3Buttons" "yes"
EndSection

Section "Monitor"

 ### Comment all HorizSync and VertSync values to use DDC:
        Identifier   "Monitor0"
        ModelName    "LCD Panel 1680x1050"
 ### Comment all HorizSync and VertSync values to use DDC:
        HorizSync    31.5 - 90.0
        VertRefresh  59.9 - 60.1
        Option      "dpms"
EndSection

Section "Device"
        Identifier  "Videocard0"
        Driver      "vesa"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        Monitor    "Monitor0"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
                Modes    "1680x1050"
        EndSubSection
EndSection

[root@localhost ~]#

What must I do to enable this resolution? Thanks in advance.

Dotan Cohen

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osor · 05-09-2007, 02:26 PM

Perhaps add a relevant modeline in the monitor section.

man 1 gtf

dotancohen · 05-12-2007, 06:50 AM

What module would that be, Osor? I cannot seem to find anything relevant. Thanks.

Dotan Cohen

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jay73 · 05-12-2007, 07:39 PM

Are you sure your xorg.conf is properly configures? It seems to me that the HorizSync anc VertRefresh under section "Monitor" don't look right. I have a 19" LCD with 1280x1024 and I use 31-82 horizontal and 31-75 vertical; by comparison, your own vertical values are 59-60 - way too low for that kind of resolution if you ask me.

osor · 05-12-2007, 08:08 PM

It’s not a module, a modeline (a line describing one of your monitor’s modes). One of your problems might be the lack of a proper mode for your monitor. Usually modes are built-in or deduced from EDID, but occasionally, (especially for funny modelines) they’re not there. Here’s an example: suppose I want to enable a mode for 1680x1050 at a “60Hz” refresh rate. Then I would run:

Code:

$ gtf 1680 1050 60
  # 1680x1050 @ 60.00 Hz (GTF) hsync: 65.22 kHz; pclk: 147.14 MHz
  Modeline "1680x1050_60.00"  147.14  1680 1784 1968 2256  1050 1051 1054 1087  -HSync +Vsync

Then, I would edit my xorg.conf

Code:

Section "Monitor"

 ### Comment all HorizSync and VertSync values to use DDC:
        Identifier   "Monitor0"
        ModelName    "LCD Panel 1680x1050"
 ### Comment all HorizSync and VertSync values to use DDC:
        HorizSync    31.5 - 90.0
        VertRefresh  59.9 - 60.1
        Option      "dpms"

        # 1680x1050 @ 60.00 Hz (GTF) hsync: 65.22 kHz; pclk: 147.14 MHz
        Modeline "1680x1050_60.00"  147.14  1680 1784 1968 2256  1050 1051 1054 1087  -HSync +Vsync

EndSection

Section "Device"
        Identifier  "Videocard0"
        Driver      "vesa"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        Monitor    "Monitor0"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
                Modes    "1680x1050_60.00"
        EndSubSection
EndSection

The green section is added (from the output of gtf), and the red section is modified to use the new modeline. HTH.

osor · 05-12-2007, 08:13 PM

Quote:

Originally Posted by jay73

I have a 19" LCD with 1280x1024 and I use 31-82 horizontal and 31-75 vertical; by comparison, your own vertical values are 59-60 - way too low for that kind of resolution if you ask me.

LCD monitors don’t have the same sort of measurements for “refresh rates” as CRT’s do. For example, I have an LCD that is currently running at 1440×900 at 56KHz horizontal frequency and 60Hz vertical frequency (those are exact numbers reported by the monitor itself).

Wim Sturkenboom · 05-14-2007, 03:40 AM

You're using the vesa driver; I don't think that that supports your resolution.