Hi grubs,

I ran into the same problem, but my display switched immediately to "input out of range". I tried three different displays and couldn't get a working display on any of them, with two good LCDs and an older tube monitor. I finally got a working display on the tube monitor after a restart with no display attached, and then hotplugging the display once everything had loaded.

It appears that the default configuration for ClearOS is to allow the kernel video drivers to automatically choose the highest available resolution reported by the display, whether the video hardware supports it or not. This creates problems on a wide range of available hardware, because DDC/EDID information from displays is very often incorrect or incomplete. Often the resolution will be reported, but the sync and ranges will be missing or incorrect. So even if the video hardware supports the output, it will often choose the wrong "default" sync for the display and you end up with nothing.

It seems that the simplest solution to solve this problem for the majority of ClearOS users is for the developers to set the output manually to an industry-standard default. For example, use one of the VESA standard resolutions (like 1024x768, 8bit, 60hz) as a fixed default for grub and X, and then provide some links to external documentation for users that want to customize the output mode via xorg.conf.

It would be great to get a comment on this from the team? Thanks for your hard work, by the way!

Best regards,

Jason Porter

Hi Jason, I agree temporarily fixing a standard resolution would be a better 'first attempt' rather than relying on the hardware to sort it self out...i'm sure the LiveCD's do something similar?

Thanks for confirming that Jason.


I think what makes this a bigger issue than it needs to be is that the graphical login is the only option selected *by default* during the installation.

A purist might also argue that X-windows is totally unnecessary on a server... but lets not go there

The fact is that for the unwary this represents a significant stumbling block during the install process. I had the benefit of a being a ClarkConnect user so knew of the text login console and was able to put 2 and 2 together (after 2 failed installations mind you!).

I figured out the root cause of the issue... the "minimized CentOS" base in the default install eliminates almost all of the standard xorg kernel module video drivers. It also eliminates the standard CentOS display configuration tool (system-config-display).

That means that for many users who have ati, s3, nvidia, matrox, or other server chipset video, there may not be any support for a working display out of the box, because the default "vesa" driver is often unable to correctly parse the DDC/EDID information being returned by the video chipset. To add insult to injury, the standard method for fixing such issues (running system-config-display) has been stripped out of the OS and is not available via yum due to unavailable redhat-related dependencies.


I solved the issue by manually installing the ati driver module (yum install xorg-x11-drv-ati) and then manually created an xorg.conf file from scratch that declares the "ati" driver in the Device section. Obviously for your own systems you should install whatever driver is appropriate, in my case the server happens to use an ATI RageXL chipset which is supported by the xorg ati driver.

My xorg.conf is very bare, it only contains this:

Section "Device"

        Identifier      "Configured Video Device"

        Driver          "ati"

EndSection



Section "Monitor"

        Identifier      "Configured Monitor"

EndSection



Section "Screen"

        Identifier      "Default Screen"

        Monitor         "Configured Monitor"

        Device          "Configured Video Device"

EndSection

Come to think of it, with the ati driver available it may not even need an xorg.conf file present, it may actually autoselect the driver... but I had already created one and it works, so I'm not doing a triple reboot just to test that.

Voila... fully working display in the LCD's native resolution with no other configuration. This should have been the default behavior... and would have been, had the ClearOS developers included the default CentOS display driver modules in the ClearOS standard build. Any chance for a revisit on this issue by the devs?

thanks for the info

Thanks for posting that Jason i've seen before instances where installation of the appropriate xorg driver has helped cure the "blank screen" issue. There is a fair selection of RPM's in the ClearOS repo - I wonder why they are not installed initially?
http://download.clearfoundation.com/clearcentos/5/os/

Hello!
I have the same problem, and I can not connect to ClearOS because power problems reset setting of network cards.
How to change the adjustment of the monitor from console?

Thank you in advance for your reply!