Ubuntu 10.04 screen resolutions

Mon May 31 17:41:13 UTC 2010

| From: marthter <marthter-FFYn/CNdgSA at public.gmane.org>

| The monitor is (quite old) ViewSonic P815
| vertical frequency range 50 - 160 Hz
| horizontal frequency range 30 - 115 kHz

Is it so old that it doesnt' support DDC?  Have a look in your
/var/log/Xorg.0.log to see what your driver finds.  For example,
here's what mine finds.  It prints it 3 times (why?).  There are not
many choices because an LCD really only wants one mode:

    (II) RADEON(0): Port1:
      XRANDR name: DVI-0
      Connector: DVI-I
      CRT1: INTERNAL_KLDSCP_DAC1
      DFP2: INTERNAL_KLDSCP_LVTMA
      DDC reg: 0x7e40
    (II) RADEON(0): I2C device "DVI-1:E-EDID segment register" registered at address 0x60.
    (II) RADEON(0): I2C device "DVI-1:ddc2" registered at address 0xA0.
    (II) RADEON(0): Output: DVI-1, Detected Monitor Type: 0
    finished output detect: 0
    (II) RADEON(0): I2C device "DVI-0:E-EDID segment register" registered at address 0x60.
    (II) RADEON(0): I2C device "DVI-0:ddc2" registered at address 0xA0.
    (II) RADEON(0): Output: DVI-0, Detected Monitor Type: 3
    (II) RADEON(0): EDID data from the display on output: DVI-0 ----------------------
    (II) RADEON(0): Manufacturer: DEL  Model: 4016  Serial#: 1194472500
    (II) RADEON(0): Year: 2005  Week: 51
    (II) RADEON(0): EDID Version: 1.3
    (II) RADEON(0): Digital Display Input
    (II) RADEON(0): Max Image Size [cm]: horiz.: 64  vert.: 40
    (II) RADEON(0): Gamma: 2.20
    (II) RADEON(0): DPMS capabilities: Off
    (II) RADEON(0): Supported color encodings: RGB 4:4:4 YCrCb 4:4:4 
    (II) RADEON(0): First detailed timing not preferred mode in violation of standard!
    (II) RADEON(0): redX: 0.640 redY: 0.343   greenX: 0.292 greenY: 0.611
    (II) RADEON(0): blueX: 0.146 blueY: 0.074   whiteX: 0.313 whiteY: 0.331
    (II) RADEON(0): Manufacturer's mask: 0
    (II) RADEON(0): Supported detailed timing:
    (II) RADEON(0): clock: 71.0 MHz   Image Size:  646 x 406 mm
    (II) RADEON(0): h_active: 1280  h_sync: 1328  h_sync_end 1360 h_blank_end 1440 h_border: 0
    (II) RADEON(0): v_active: 800  v_sync: 803  v_sync_end 809 v_blanking: 823 v_border: 0
    (II) RADEON(0): Supported detailed timing:
    (II) RADEON(0): clock: 268.0 MHz   Image Size:  646 x 406 mm
    (II) RADEON(0): h_active: 2560  h_sync: 2608  h_sync_end 2640 h_blank_end 2720 h_border: 0
    (II) RADEON(0): v_active: 1600  v_sync: 1603  v_sync_end 1609 v_blanking: 1646 v_border: 0
    (II) RADEON(0): Monitor name: DELL 3007WFP
    (II) RADEON(0): Serial No: JG5785CFG244
    (II) RADEON(0): EDID (in hex):
    (II) RADEON(0):         00ffffffffffff0010ac164034343247
    (II) RADEON(0):         330f01038040287828fe87a3574a9c25
    (II) RADEON(0):         13505400000001010101010101010101
    (II) RADEON(0):         010101010101bc1b00a0502017303020
    (II) RADEON(0):         360086962100001ab06800a0a0402e60
    (II) RADEON(0):         3020360086962100001e000000fc0044
    (II) RADEON(0):         454c4c20333030375746500a000000ff
    (II) RADEON(0):         004a47353738354346473234340a0007
    finished output detect: 1

When I've used monitors without DDC/DDC/EDID support, some xorg
drivers are startled and misbehave.  Although lack of such support is
legal, almost nobody has such a setup so the xorg code is not well
tested for that case.

See, for example,
<https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-savage/+bug/217004/comments/10>

| Its user guide is a little vague on its true maximum resolution... if it is to
| comply with FCC class B it says its max is 1600x1200.

That requirement is to do with RF emision.  I guess that if you crank
up the resolution, airplanes might fall out of the sky and garage
doors might spontaneously open.

| xrandr: screen cannot be larger than 1792x1344 (desired size 1920x1440)

I wonder why?

In the old days (it may have changed) the frame buffer got allocated
for the startup resolution (but you could specify larger) and then you
could not switch to a resolution that would not fit in that
space.  But that would be a limit on the product of dimensions, not
each dimension.

Some video hardware can only do some kinds of acceleration (3d?) at
resolutions that are lower than what they can do 2d at.  Maybe that is
what you are hitting.  A GeForce 6150SE nForce 430 is pretty weak.

Are you using DVI?  Unless you are using dual-link DVI (I don't think
you are), the bandwith limit is 1920x1200 at 60Hz if I remember
correctly.  I guess you are using VGA given the age of the monitor.  I
don't know the limit in that case.

Dunno.
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