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[jack21]

I thought I'd share this info - maybe it will help others.

Last weekend I was prompted to (re)try Ubuntu 12.04LTS on a multi-boot test rig.....a Dell Dimension E520 with a HD2400 graphics card. The install did not recognise the monitor type and provided a basic driver at 1024*768 - no higher sizes. I experimented with various ATI drivers, ranging from the latest (12.4) down into the 11.x range; all installed, but on rebooting the monitor screen went black and gave a message 'Unable to display this resolution' - I could find no way to get a display from which I could deinstall the drivers. Reinstalls of Ubuntu, followed by driver installs gave no improvement.....then I switched to Linux Mint 12 and found the same problem. But PClinuxOS 2012.02 recognised the monitor and card correctly and worked perfectly.

Eventually I had some inspiration; a few months ago I recalled having difficulty redirecting video from a laptop to a Sony TV, and finding that only one of the seven VGA monitor cables I have was recognised by the TV. So I tried that specific cable on the test rig, and wonders, all now worked fine.........installs of Ubuntu 12 and Mint 12 'worked out of the box', the monitor was recognised and the higher resolutions were present. I tested my 7 cables; just the one had all 15 pins connected end-to-end, whereas the others had as many as 6 (I think) pins not connected thru.  I've now ordered a couple more cables advertised as having all pins connected........and a DVI-D cable to try-out.

[roseway]

That isn't a problem I've come across, but it's useful to know, thanks. I would guess that the missing connections are the ones which provide the EDID information, so the driver doesn't know the capabilities of the monitor. It should be possible to force the resolution you want without this information, by using a utility like Xrandr, or by editing xorg.conf manually, but having the EDID information available makes setting up much easier.

[tickmike]

That's a new for me, I will do some tests on some of the cables I have.

[asbokid]

I thought I'd share this info - maybe it will help others.

Last weekend I was prompted to (re)try Ubuntu 12.04LTS on a multi-boot test rig.....a Dell Dimension E520 with a HD2400 graphics card.

The ATI Radeon HD2400 is powered by ATI's R600 series GPU.

The install did not recognise the monitor type and provided a basic driver at 1024*768 - no higher sizes. I experimented with various ATI drivers, ranging from the latest (12.4) down into the 11.x range; all installed, but on rebooting the monitor screen went black and gave a message 'Unable to display this resolution'

The X server uses a fail-safe humble screen resolution when a number of problems are encountered, including an incorrect/incompatible/ill-configured video driver, etc..

The xorg logs should reveal exactly the problem.. post the log here if you want, although one of the full-blown Linux forums will serve you better..

- I could find no way to get a display from which I could deinstall the drivers.

Normally however borked X windows has become, the key combination [ctrl][alt][f1] or [ctrl][alt][f2].. up to..[ctrl][alt][f6] will get you a console login screen.

And in debian, and presumably ubuntu, [ctrl][alt][f7] should get you back to X windows (if the x server is running at all).

Or wasn't that the problem?

Reinstalls of Ubuntu, followed by driver installs gave no improvement.....then I switched to Linux Mint 12 and found the same problem. But PClinuxOS 2012.02 recognised the monitor and card correctly and worked perfectly.

Take a note of the version number of the X.org server running in PCLinuxOS, and closely study the Xorg logs under /var/log/Xorg....log.   Compare them with the same x server logs from the distros that won't drive the screen beyond 1024x768.

The problem could be with the build configuration for the ubuntu kernel and/or the device driver module(s) for that video card.

Good luck!
cheers, a

[jack21]

Thanks Askbokid, those control-alt key combos are now noted - they would have been, and will be, very useful to me to get a working console if similar issues arise.

At one point I recall accessing the xorg.conf file (via one of the other installed linus o/s) and being surprised to find it virtually empty - just a small section with no refs to resolution..........the details are fading, but I also recall finding no xorg.conf file present at some point when I was comparing the PClinux and Ubuntu xconfigs.

However, since the 15-pin discovery, I was then able to make progress with the task in hand - doing an assessment of some of the latest variants of my favourite Linux issues - Linux Mint 12 (and its KDE and LXDE variants), PCLinuxOS 2012 and all its variants, and giving the 2012.04 Ubuntu, Kubuntu and Xubuntu a try-out; I haven't revisited the issue using the non-15 cables. I've also now got myself a DVI-D cable from the rig to the monitor; that also enables the Ubuntu derivatives to work out of the box.

I left Windows back in 2008 for SUSE 10, and just have XP as a multi-boot option - primarily to occasionally get at Flight Simulator!. Although I've 'flirted' with Linux Mint since its Gloria release, it wasn't till 2010 that I switched my main day-to-day desktop to Linux Mint (away from SUSE 11 - because of severe graphics issues when upgrading from 11.1 to 11.4)......and I'm very happy indeed with my current Mint 11. I found PClinuxOS suited me/pc best of all on my Presario 4000 laptop, and Puppy Linux invaluable on my very elderly Toshiba SP 4600 take-everywhere-for-diagnostics machine. The cold and wet weather gave me an opportunity to check-out more recent releases......and I've concluded that Unity and/or Gnome 3 are not my style at all......previously a Gnome 2 fan (and therefore of MATE and PClinux), I'm now also finding the X versions of Ubuntu, and PClinux quite appealing.......less so the KDEs.

Cheers
Jack

[broadstairs]

This thread has interested me, as I've never come across a problem with my cables either.

As to the Linux distros I have concluded that Ubuntu in its various guises is not for me mainly as I dont like the intention it seems to have to prevent doing anything under the covers easily. I did run PCLinux for a while in its KDE form but have now moved to Fedora again in KDE form and so far for me it has been the best I've tried. Using KDE seems natural to me plus I can get my wife to use Linux as I can get it to look like her old Windows system  I have never liked Gnome in any of its guises.

I do till have XP both in Virtualbox and as dual boot for a couple of things which are not (yet) do-able in Linux.

Stuart

[roseway]

At one point I recall accessing the xorg.conf file (via one of the other installed linus o/s) and being surprised to find it virtually empty - just a small section with no refs to resolution..........the details are fading, but I also recall finding no xorg.conf file present at some point when I was comparing the PClinux and Ubuntu xconfigs.

A year or so ago, xorg was upgraded to use fully automatic configuration by default. Every time it's launched, it reads the EDID information from the monitor, and config information from the mouse, keyboard etc., and sets the parameters accordingly, without recourse to an xorg.conf file. However it still respects xorg.conf if it's available, and this is sometimes needed when the automatic setup doesn't work correctly.

[burakkucat]

Just a couple of comments, to build on Asbokid's and Eric's advice.

Another key combination to note is <Ctrl><Alt><Backspace>, which should restart the system's X-server.

The more recent versions of Xorg have an in-built version of xorg.conf which will be used as a fail-safe. It is possible to force the X-server to dump a copy to the log file (I forget how I achieved that    ) and then, by copying the log file and selective editing, create a viable minimal version of xorg.conf applicable to the relevant distributions' version of Xorg. Further additions can then be made to that file.

[roseway]

Another key combination to note is <Ctrl><Alt><Backspace>, which should restart the system's X-server.

That's sometimes very useful, to get out of a locked-up situation. But it may be disabled with recent versions of xorg, depending on your particular distro. If it is disabled, it can be reenabled by adding the following line to /home/yourname/.xinitrc:

setxkbmap -option terminate:ctrl_alt_bksp

[asbokid]

Another key combination to note is <Ctrl><Alt><Backspace>, which should restart the system's X-server.

That's sometimes very useful, to get out of a locked-up situation. But it may be disabled with recent versions of xorg, depending on your particular distro. If it is disabled, it can be reenabled by adding the following line to /home/yourname/.xinitrc:

setxkbmap -option terminate:ctrl_alt_bksp

Excellent advice, as ever, from Roseway.

If you get really stuck, obtain a text console with [ctrl][alt][F1] and log in.

Then re-start the X server by issuing the following command:

sudo killall -HUP Xorg

cheers, a