Comment 8 for bug 201491

I'm forwarding this bug report from a Ubuntu user:
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/201491

With a Iiyama monitor, xdpyinfo reports 300x230mm yet the actual physical size differs. Xorg.0.log lists the correct dimensions (no mention of 300x230mm in the log), and ddcprobe and xrandr also both report the correct dimensions.

Looking through the xdpyinfo code and referring to xlib's implementation of DisplayHeightMM() and DisplayWidthMM(), I didn't spot code that manipulates those values or sets them to default values, so my guess is the EDID from the monitor simply needs quirked? Does it need quirk_detailed_use_maximum_size() like the LPL monitors?

Iiyama ProLite E431S, ATI Radeon 9800 Pro, DVI, -ati
Manufacturer: IVM Model: 46ac Serial#: 16832

== Original Report ==
Binary package hint: xorg

It seems tools like xdpyinfo are reporting screen sizes as 300x230 mm in a lot of cases when they are not.

On my own Iiyama ProLite E431S with an ATI Radeon 9800 Pro connected over DVI using the "ati" driver, I get this from xdpyinfo:

screen #0:
  dimensions: 1280x1024 pixels (300x230 millimeters)
  resolution: 108x113 dots per inch

ddcprobe correctly detects the screen physical dimensions:

screensize: 34 27

In another report, https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/201032 the reporter shows that xdpyinfo quotes:

screen #0:
  dimensions: 1280x800 pixels (300x230 millimeters)
  resolution: 108x88 dots per inch

and ddcprobe reports:

screensize: 33 21

Notice that the screens are actually different dimensions, both in physical terms and pixel terms, yet xdpyinfo thinks they are 300x230 mm. Also, the other reporter is using the intel driver.

This did indeed used to work correctly in the early Hardy alphas, and previous releases of Ubuntu.

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[Note that the bug the user references is about a LGPhilipsLCD LP154W01-TLD (LPL prod id 48128) monitor, which might be similar to the LGPhilipsLCD LP154W01-A5 from bug #10304, which is quirked with quirk_detailed_use_maximum_size().]