Kernel 2.6.34 with intel 2.11 blank screen [Solved]

[iki]

Have a fresh install of 20100515 KDE amd64 iso on Acer Thinline 3810T. It rocks!

Updated kernel to linux-sabayon-2.6.34 (both r0 and r1 yesterday), rebooted, X started and the screen went blank with blinking cursor in top left corner, and /var/log/Xorg.0.log stated:

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(II) Primary Device is: PCI 00@00:02:0
(EE) intel(0): No kernel modesetting driver detected.
(II) UnloadModule: "intel"
(EE) Screen(s) found, but none have a usable configuration.


The driver used was xf86-video-intel-2.11.0. Kernel linux-sabayon-2.6.33 worked ok.

After some search (links below) I figured I should force kernel modesetting for the intel driver module.
I didn´t research yet how to add kernel parameters to grub2 (1.98-r4 /r1). I learned how to build /boot/grub/grub.cfg via

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sudo /sbin/grub-mkconfig -o /boot/grub/grub.cfg

, but did not find where to edit the kernel parameters in grub-mkconfig source config files /etc/grub.d/* and /etc/default/grub. Is it the GRUB_CMDLINE_LINUX in /etc/default/grub? What kernels does it apply for? What is /proc/cmdline that contains default value? And what is GRUB_CMDLINE_LINUX_DEFAULT for? I don´t know yet.

But I found the following way how to force modesetting for the driver module and solve the issue, independently on kernel parameters in grub:

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echo options i915 modeset=1 > /etc/modprobe.d/i915-kms.conf

See also:
viewtopic.php?f=86&t=20503
viewtopic.php?f=76&t=20492#p116105
http://en.gentoo-wiki.com/wiki/Intel_GMA
http://en.gentoo-wiki.com/wiki/Kernel_Mode_Setting
https://wiki.ubuntu.com/X/KernelModeSetting

[joost]

http://lists.sabayon.org/pipermail/deve ... 02072.html

Funny, I was working on that yesterday, glad you sorted it out.

About grub:
http://joostruis.wordpress.com/

And ironically I discussed this with Lxnay this morning:
http://gitweb.sabayon.org/?p=overlay.gi ... ed21fd14ba

So it will have a bit more info in there.

[iki]

Glad, it helped Your presumption was right, /etc/modprobe.d/* seem to be loaded automatically and it works out of the box.

Btw, thanks for the hint /etc/default/grub in the git repo link and your blogpost on it. So GRUB_CMDLINE_LINUX_DEFAULT is appended to GRUB_CMDLINE_LINUX, right?

Just wondering, why 2.6.33 works without that... Does it have the module compiled in (with modesetting enabled)?

[joost]

In .33 kernel the modesettings was off by default (m), in .34 it is on by default (y).
We will most likely revert this change to have it off by default and use the moprobe.d file for Intel to overrule it.

[lxnay]

KMS for i915 is defaulted to off. I think we should enable KMS for intel.

[lxnay]

iki, are you on amd64?

[lxnay]

If you're on amd64, I'm recompiling the kernel with KMS enabled for intel. That will fix your issues without any further "hack" around. x86 kernels had KMS for intel enabled already, weird.

[iki]

Yes, it´s 20100515 KDE amd64 iso.

Intel 2.11 with KMS works OK here with both 2.6.33 (out of the box) and 2.6.34 (with KMS forced via /etc/modprobe.d/i915-kms.conf).

OK, I´ll try the kernel with enabled KMS for intel as soon as it is in standard repo and let you know.

[lxnay]

Updates have been pushed

[iki]

... and tested, at least on amd64

The r2 of 2.6.34 kernel now works OK with the intel driver even without KMS being explicitly enabled (eg. in /etc/modprobe.d/).

Thanks