[SOLVED] Intel i915 3.14.14 systemd: KMS Blank screen

[Sulman]

Hi all,

An unusual problem. I was building a laptop and completed the build to first reboot using OpenRC without problems.

I decided to migrate to systemd (I've been trying it on a few boxes recently) and this was smooth as per the systemd wiki, but something has happened to my Intel KMS framebuffer; after a normal GRUB startup and initramfs, when the KMS should start my screen goes blank.

The screen backlight is on (hotkeys for brightness work too), but there is no display. I can SSH to the box, journalctl shows a normal boot, but I have no display.

I can get it working passing nomodeset=1 to the Kernel parameters, but obviously lose KMS.

What I have tried:

Tried the i915 drivers as builtin and as modules (no difference).
nomodeset=1 works to get a simple console.
Double checked my .config as per http://wiki.gentoo.org/wiki/Intel

This is an intel core 2 based laptop (a Toshiba Satellite Pro L300) and I'm using a GPT partitioned disk with regular BIOS.

Worst comes to the worst I'll just rebuild/switch it with OpenRC again, but the problem has me curious. I feel like I'm missing something obvious but the fact it all worked under OpenRC has really confused me.

[Sulman]

I am still utterly puzzled, have tried virtually every kernel command line going (between the Gentoo and Arch wikis), but I have discovered something interesting: If I suspend and resume (suspend via ssh), all is well, but after a reboot it's back to the way it was before. Backlight on but no display: It is apparently something to do with power management.

Dmesg,Xorg0.log, and journalctl show normal boots. KDM is sitting there waiting for me to login, I just can't see it.

I've spent many hours on this now, and seem tantalisingly close to a solution, but I could conceivably keep looking for many hours longer and not find it, so I think I'm going to throw in the towel and rebuild with OpenRC.

The same laptop used to run Arch (I just prefer Gentoo nowadays and had been meaning to rebuild it for a while) and as far as I can tell the only thing that Arch does differently is allowing the possibility of an early KMS start through mkinitcpio.

I suppose my big question is, what on earth could systemd be doing to cause a display to misbehave?

[Sulman]

Fixed it - upgrading to 3.16 has solved it. This thread persuaded me to try a newer kernel and - lo and behold - it worked; everything is now as it should be.