ubuntu-x-swat team mailing list archive

[Hadmut Danisch <hadmut@xxxxxxxxxx>]

Public bug reported:

Binary package hint: xserver-xorg

Hi,

this is rather a wish than a bug report.

I connected an ubuntu machine with an HDMI cable to a small LCD TV.
Unfortunately, the TV's firmware is not that good. Although the TV has a
1366x768 panel, it only lists 1920x1080 and 720x480 as possible
resolutions. The X11 server refuses to use any other than those two
listed resolutions, even if configured in xorg.conf. (The manufacturer
says, it is not possible to use the TV with any other resolution, not
even in the panel's resolution of 1366x768.) Unfortunately it is
impossible to get an acceptable resolution, because 1920x1080 is scaled
down and blurred, while 720x480 is scaled up and again, blurred.

But then something curios happened: Accicendtly I pulled a little bit at
the HDMI cable and it slipped out of the plug just a little bit.

Then, the BIOS and Linux in console mode did not show anything on the TV
anymore and instead used the analog VGA port. But once the X11 server
started, it chose the resolution of 1366x768 as configured in xorg.conf,
and even the TV accepted it, displaying 1360x768 as resolution (don't
ask me why it detected 1360 instead of 1366), and the display was
absolutely sharp and perfect, and in the correct resolution.

So I guess that the losen HDMI cable allowed to transmit the signal from
the PC to the TV, but not from the TV to the PC. PC could not detect the
TV and read its table.


This shows that it would be usefull to have an option to force the X11 server to ignore the resolution table reported by the screen on DVI and HDMI and to rigorosly use the given resolution as an override, in order to circumvent firmware problems as described. 

regards

** Affects: xorg (Ubuntu)
     Importance: Undecided
         Status: New

-- 
Need to override HDMI resolution list
https://bugs.launchpad.net/bugs/409018
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