[CentOS] Questions about kernel updates

Sun Nov 4 18:57:04 UTC 2007
Robert <kerplop at sbcglobal.net>


Johnny Hughes wrote:
> Robert wrote:
>   
>> The latest CentOS 5 kernel, 2.6.18-8.1.15.el5 broke my box and I had to
>> drop back to 2.6.18-8.1.14.el5 before I could play DVDs with either Xine
>> or mplayer. ( xine-0.99.5-1.el5.rf & mplayer-1.0-0.36.rc1try2.el5.rf ).
>> This is no big deal to me  -- as long as I can make certain that  the
>> older kernel doesn't go away.
>> If I understand the installonly plugin correctly, an entry of tokeep=4
>> in /etc/yum/pluginconf.d/installonlyn.conf will cause yum to leave the
>> working kernel in place through 2 more upgrades.  Aside from setting
>> tokeep to an insanely large value, is there any way to insure that yum
>> will concern itself only with installing updates, allowing me to deal
>> with tossing the old stuff?  Also, is my understanding of the "tokeep"
>> value in installonlyn.conf correct?
>>     
>
> Yes ... you can just turn that plugin off
>
> set enabled=0 in installonlyn.conf and it will never delete a kernel.
>
> You could also add this to the CentOS-Base.repo file in
> /etc/yum.repos.d/ in the [Base] and [updates] sections:
>
> exclude=kernel kernel-headers kernel-devel kernel-PAE* kernel-xen*
>
> then you will have to manually upgrade your kernels ... if you wanted that.
>
> I will test the DVD playback issues and see if I can duplicate them.
>
> Thanks,
> Johnny Hughes
>   
Don't spend any time on it.  You might or might not be able to duplicate 
the problem. The bug is a bug only to the extent that a new kernel 
really shouldn't cause previously working stuff to suddenly fail.  I 
think it goes back to the way device allocation rules seem to be a 
moving target.

Using the previous kernel:

    [root at mavis dev]# uname -r
    2.6.18-8.1.14.el5
    [root at mavis dev]# ls -l dvd*
    lrwxrwxrwx 1 root root 3 Nov  4 12:39 dvd -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:39 dvd-hdc -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:39 dvd-hdd -> hdd
    lrwxrwxrwx 1 root root 3 Nov  4 12:39 dvdrw -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:39 dvdrw-hdc -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:39 dvdwriter -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:39 dvdwriter-hdc -> hdc
    [root at mavis dev]#



Using the new kernel:

    [root at mavis dev]# uname -r
    2.6.18-8.1.15.el5
    [root at mavis dev]# ls -l dvd*
    lrwxrwxrwx 1 root root 3 Nov  4 12:05 dvd -> hdd
    lrwxrwxrwx 1 root root 3 Nov  4 12:05 dvd-hdc -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:05 dvd-hdd -> hdd
    lrwxrwxrwx 1 root root 3 Nov  4 12:05 dvdrw -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:05 dvdrw-hdc -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:05 dvdwriter -> hdc
    lrwxrwxrwx 1 root root 3 Nov  4 12:05 dvdwriter-hdc -> hdc
    [root at mavis dev]#             

So that the generated symlink for dvd now points to a different drive.
The workaround for xine is to change the value of media.dvd.device in 
~/.xine/config accordingly:

    [rj at mavis .xine]$ grep -B3 media.dvd.device config

    # device used for DVD playback
    # string, default: /dev/dvd
    media.dvd.device:/dev/dvd-hdc
    [rj at mavis .xine]$

So, it's really nothing for me to get my skivvies in a wad over but it 
is a bit annoying when stuff suddenly quits working.

Regards