Screen blanks in X beginning with kernel 3.1 (and up)
 

When I start X the screen goes blank and stays permanently blank in X. It works: I can do things that make sounds, create files, and quit. I can switch out of X and unblank the screen, but it goes back to being blank when I switch back to X. The problem doesn't happen in 3.0.9.

Slackware, updated daily; eMachines e725-4250 laptop, Intel i915 video chip.

I had the same problem with some 2.6.? kernels and built my own X. I don't want to do that again.

bugzilla.kernel.org doesn't work: is there another place to post kernel bugs?

If you list the steps, to reproduce it, someone might be able to help.
How do you start X? Etc.

What makes you think it's a kernel bug?
Sometimes going through creating the bug report can offer new insights. But you don't need bugzilla.kernel.org to create the report.

I run startx. There are no other steps.

It doesn't happen with any 3.0.? kernel and happens with every 3.1.? kernel.

After creating the bug report I still didn't solve the problem. I wanted to post it in bugzilla.kernel.org in case it was a kernel bug. A previous kernel had the same problem. I hoped to get the attention of the kernel-persons so that they would either fix it or point to the place in the kernel relevant to the problem where I could patch it.

What's in Xorg.0.log? Etc.
Did you diff -up .config.3.0 .config.3.1?
And like that.

What virt tty did you startx from? Can you ctrl-alt-F1 or F2 ,etc.?

Xorg.0.log is no different.

There is nothing different in /var/log/syslog, messages, or debug.

Yes. There are many differences.

10, usually, but the same happens from 1 or 6.

Yes. As my original post says, I can switch to a non-X virtual terminal and unblank; when I switch back it blanks again.

Probable Red-Herring Alert:
"X" is an application that actually has nothing to do with "the kernel."

'X' has a lot to do with the kernel. This problem doesn't happen with versions 3.0.? but does with all versions 3.1.?; the kernel handles blanking.

Maybe this is a driver issue. What display driver is being used? If you don't have an xorg.conf in /etc/X11, create one using , copy over the resultant xorg.conf to /etc/X11/ and try to change the display driver to vesa and see if that helps.

In reply to the assertion that X is an app that has nothing to do with the kernel I quote drivers/gpu/drm/README.drm:

I solved the problem by using the drivers/gpu/drm/drm_crtc_helper.c from kernel 3.0. The drm_crtc_helper.c for version 3.1 has these additional lines:

which are in the drm_crtc_helper_set_config routine.

There is nothing wrong with the configuration file.