Comments on: HOWTO: Enabling Kernel Mode Setting (KMS) in Debian Linux kernel

By: baccy

baccy — Fri, 22 Jan 2010 22:58:17 +0000

Thanks for this very helpful article! I managed to get a beautiful 1920×1200 framebuffer with a radeon M66-P running squeeze on my asus laptop.

At the moment squeeze is still using a 2.6.30 kernel, but the following sid packages installed just fine:

* linux-image-2.6.32-trunk-686
* firmware-linux-nonfree
* firmware-linux-free

The only problem was the automatic start of the framebuffer. Appending these lines to /etc/initramfs-tools/modules resulted in a crash at boot:

ati_agp
drm
radeon modeset=1

Maybe I missed something important. Here’s how I ‘fixed’ it:

Create the file ‘radeon_framebuffer.conf’ in /etc/modprobe.d/ with the following content:

options radeon modeset=1
install video /sbin/modprobe radeon; /sbin/modprobe –ignore-install video

By: kwinz

kwinz — Sat, 28 Nov 2009 05:07:53 +0000

I found out that your kernel boot parameter is wrong.

DOES NOT WORK:
video=i915:modeset=1

WORKS:
i915.modeset=1

By: Russell Senior

Russell Senior — Sat, 21 Nov 2009 05:47:06 +0000

the mouse thing was a sawfish (wm) problem, that’s fixed, but freezes persist. multiple X sessions (startx — :1, startx — :2, etc) seems to exacerbate).

By: Russell Senior

Russell Senior — Fri, 20 Nov 2009 08:26:52 +0000

I had a debian/unstable box with i915 hardware (which has been freezing in X for weeks) suddenly stop recognizing its right mouse button last night. I get errors in Xorg.0.log about i810 module being missing and /dev/fb0 (no such file or directory).

By: Akis Foulidis

Akis Foulidis — Wed, 18 Nov 2009 03:53:27 +0000

I believe this error is about the i2c connection via the DDC wire in order to get information from the monitor. Anyway, my KMS is still available and the error from the X server was irrelative.

By: Admin

Admin — Wed, 18 Nov 2009 03:06:40 +0000

I think it is a bug in the kernel which I believe will be fixed in next release..See some links at:
http://www.google.com/search?hl=en&rlz=1B5GGGL_enUS318US319&q=drm%3Aintel_dp_i2c_init+*ERROR*++error&btnG=Search&aq=f&oq=&aqi=

By: Akis Foulidis

Akis Foulidis — Wed, 18 Nov 2009 00:09:50 +0000

Let me also add that my X freezes and I can’t go to a virtual terminal or kill the X server. I believe that might be an xorg.conf error though and not the drm error in the kerner buffer that I mentioned above.

By: Akis Foulidis

Akis Foulidis — Wed, 18 Nov 2009 00:06:08 +0000

Hello and nice article. The thing is that I have in dmesg the “[drm:intel_dp_i2c_init] *ERROR* i2c_init DPDD-B (& C) error”. It was a bug that was fixed last month I believe.

Anyway, my kernel is 2.6.31.6 and I have the latest intel driver installed and I can’t get rid of this error. Is there something in the kernel that I might have missed (apart from the framebuffer and KMS modules that are confiugred correctly) ?

By: Stéphane Péchard

Stéphane Péchard — Thu, 05 Nov 2009 09:47:15 +0000

yes, i use the i915 driver, is it wrong?

By: Admin

Admin — Thu, 05 Nov 2009 09:26:44 +0000

What driver are you trying to use? i915?

By: Stéphane Péchard

Stéphane Péchard — Wed, 04 Nov 2009 08:15:38 +0000

Each time I tested this on my eeepc, keyboard and mouse are freezed after hibernation
Hope hurther versions of kernel and xserver-xorg-video-intel will correct this.

By: Admin

Admin — Wed, 04 Nov 2009 06:33:22 +0000

Hi Oren,

You are right. Unstable = Coolness (wrt latest software).

I wanted to write the article with regards to all kinds of Debian branches – Stable, Testing, Unstable. Also I wanted to cover some basic background on this subject.

By: Oren

Oren — Wed, 04 Nov 2009 06:18:36 +0000

In latest Debian sid, all I have to do was:
rmmod i915
modprobe i915 modeset=1

(or add options i915 modeset=1 to /etc/modprobe.d/i915.conf)

Coolness!

By: Admin

Admin — Tue, 03 Nov 2009 22:03:50 +0000

I have updated the post with some further clarification

By: Admin

Admin — Tue, 03 Nov 2009 20:18:28 +0000

Jason,

For your first point, I have a kernel from Debian testing and KMS is not enabled by default:
debian:~# cat /boot/config-2.6.30-1-686 | grep KMS
# CONFIG_DRM_I915_KMS is not set

As for the FB modules, you might be right one does not need to completely remove them but they need to make sure that none of the FB modules are compiled in (y) instead they are just modules(m).

For the second point, I have mentioned that in my post that if you have a particular version and above of initramfs you don’t need to update your initrd.