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

RandomTroll · 11-28-2011, 09:07 PM

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?

timetraveler · 11-29-2011, 09:51 PM

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.

RandomTroll · 11-30-2011, 08:03 PM

Quote:

Originally Posted by timetraveler

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

I run startx. There are no other steps.

Quote:

Originally Posted by timetraveler

What makes you think it's a kernel bug?

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

Quote:

Originally Posted by timetraveler

you don't need bugzilla.kernel.org to create the report.

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.

timetraveler · 11-30-2011, 11:31 PM

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.?

RandomTroll · 12-02-2011, 07:01 PM

Quote:

Originally Posted by timetraveler

What's in Xorg.0.log?

Xorg.0.log is no different.

Quote:

Originally Posted by timetraveler

Etc.

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

Quote:

Originally Posted by timetraveler

Did you diff -up .config.3.0 .config.3.1?

Yes. There are many differences.

Quote:

Originally Posted by timetraveler

What virt tty did you startx from?

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

Quote:

Originally Posted by timetraveler

Can you ctrl-alt-F1 or F2 ,etc.?

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

sundialsvcs · 12-02-2011, 09:30 PM

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

RandomTroll · 12-06-2011, 01:45 AM

Quote:

Originally Posted by sundialsvcs

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.

vharishankar · 12-06-2011, 01:53 AM

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

Code:

X -configure

, copy over the resultant xorg.conf to /etc/X11/ and try to change the display driver to vesa and see if that helps.

RandomTroll · 12-06-2011, 11:30 PM

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:

Quote:

The Direct Rendering Manager (drm) is a device-independent kernel-level
device driver that provides support for the XFree86 Direct Rendering
Infrastructure (DRI).

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:

Quote:

562a563,567
> } else if (set->fb->depth != set->crtc->fb->depth) {
> mode_changed = true;
> } else if (set->fb->bits_per_pixel !=
> set->crtc->fb->bits_per_pixel) {
> mode_changed = true;

which are in the drm_crtc_helper_set_config routine.

There is nothing wrong with the configuration file.