Kernel update and "KMS"

jdarnold · 2009-12-30 15:11:35

Pardon my ignorance, but I don't know what "KMS" means, and I have a pacman -Syu asking to upgrade my kernel. But the Arch Linux "latest news" says:

Early userspace KMS support is broken at the moment for radeon
and nvidia cards. There are some workarounds posted on the ML and on the forum.
Next mkinitcpio update will fix this regression in the future.

what is KMS, what does it mean to be "broken", and how is it fixed? I have an nVidia 8600 and don't feel the need to be cutting edge, so I'd be glad to wait until the "mkinitcpio update" comes along. I suppose chances are I could do the update and it would work (he says with fingers and toes crossed), and use the info posted in another thread to back out the kernel change if it doesn't?

Zariel · 2009-12-30 15:22:51

If your using Nvidia and not using Nouveau drivers then your fine, KMS is kernel based mode setting.

nitralime · 2009-12-30 18:40:48

I have also an nvidia card and using nvidia driver.
But after upgrading to kernel 2.6.32 I encountered a nasty problem
which I have described in http://bbs.archlinux.org/viewtopic.php?id=87728.
I couldn't find any workaround until now:-(

Regards
Nik

flamelab · 2009-12-30 18:45:08

jdarnold wrote:

Pardon my ignorance, but I don't know what "KMS" means, and I have a pacman -Syu asking to upgrade my kernel. But the Arch Linux "latest news" says:
Early userspace KMS support is broken at the moment for radeon
and nvidia cards. There are some workarounds posted on the ML and on the forum.
Next mkinitcpio update will fix this regression in the future.
what is KMS, what does it mean to be "broken", and how is it fixed? I have an nVidia 8600 and don't feel the need to be cutting edge, so I'd be glad to wait until the "mkinitcpio update" comes along. I suppose chances are I could do the update and it would work (he says with fingers and toes crossed), and use the info posted in another thread to back out the kernel change if it doesn't?

Read the ATi wiki page for more info. It mostly affects ATi users.

jdarnold · 2009-12-30 19:38:34

Ahh, thanks for the pointer to the ATI wiki page. Still not sure I want to take the 2.6.32.2 plunge yet though. If I copy my /boot folder to say, /boot.bak, and I have problems with the update, can I just move boot.bak back as boot and have it work?

jdarnold · 2009-12-30 19:40:57

Concise downgrading instructions are posted here:

http://bbs.archlinux.org/viewtopic.php? … 65#p679565

jdarnold · 2009-12-30 20:01:08

Well, I'm going to take the plunge. If you don't hear from me in a few hours, send in a rescue party

jdarnold · 2009-12-30 20:27:57

Well, that kernel update seemed to work just fine for me. Thanks again everyone!

doby · 2009-12-31 08:54:36

Hi everybody,

I have some questions regarding KMS. During the boot process, "small" font appears just after grub or after udev loading ? The "small" font cover the entire screen or just the left half until entering in runlevel 3 ? Best regards.

litemotiv · 2009-12-31 09:15:11

doby wrote:

Hi everybody,
I have some questions regarding KMS. During the boot process, "small" font appears just after grub or after udev loading ? The "small" font cover the entire screen or just the left half until entering in runlevel 3 ? Best regards.

the small text are the regular bootmessages, but in your screen's native resolution (that is one of the things that kms does). if you want a little less text you can add the word "quiet" (without quotes) to your kernel boot line in /boot/grub/menu.lst

doby · 2009-12-31 09:27:59

@litemotiv

Thanks for the grub stuff, I already use it. The question is more : do you have the native resolution right after grub or just after udev loading ? And the second question is : do you have the native resolution or a smaller one then the native during the boot process. When I enabled KMS, I got the "ancient" style bootmessages (large font), then I have the bootmessages in a smaller font but only in the left half of my screen. After entering in runlevel 3, the bootmesages are displayed with the correct resolution (1280x800). I looked the dmesg output and see something relative to drm TV out. Topics relative to this issue deal with ATi cards but I have an Intel 945GM card so no solution in the ATi threads.

litemotiv · 2009-12-31 10:49:43

@doby: you only have the kms resolution after the modules are loaded, so generally that is after udev. if you want them earlier you have to load them in your initramfs. more information here:

http://wiki.archlinux.org/index.php/Int … Setting.29

note that even in initramfs with 'quiet' you will still see some large text go by, since there is a bit of other initialization before the modules are loaded.

(i have both ati 3650 and intel 945 here, and the process is similar for both cards)

Last edited by litemotiv (2009-12-31 10:52:13)

doby · 2010-01-06 08:59:35

@all : Happy new year
@litemotiv : Thanks for your help. I have already read the link you gave me. I also have made a fresh install in an other laptop with an nvidia card. Same boot process as mine. Looking at dmesg output, lines with "[drm]TV-out" and "[drm]LVDS resolution" change the resolution of the screen when entering in runlevel 3 (disconnect TV out and use full resolution for LVDS panel). This is weird but not a problem. I see if I found something new. Anyway thanks for your time.

Arch Linux

#1 2009-12-30 15:11:35

Kernel update and "KMS"

#2 2009-12-30 15:22:51

Re: Kernel update and "KMS"

#3 2009-12-30 18:40:48

Re: Kernel update and "KMS"

#4 2009-12-30 18:45:08

Re: Kernel update and "KMS"

#5 2009-12-30 19:38:34

Re: Kernel update and "KMS"

#6 2009-12-30 19:40:57

Re: Kernel update and "KMS"

#7 2009-12-30 20:01:08

Re: Kernel update and "KMS"

#8 2009-12-30 20:27:57

Re: Kernel update and "KMS"

#9 2009-12-31 08:54:36

Re: Kernel update and "KMS"

#10 2009-12-31 09:15:11

Re: Kernel update and "KMS"

#11 2009-12-31 09:27:59

Re: Kernel update and "KMS"

#12 2009-12-31 10:49:43

Re: Kernel update and "KMS"

#13 2010-01-06 08:59:35

Re: Kernel update and "KMS"

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