[elrepo] Today's nvidia 340xx update

[Phil Perry]

On 05/08/15 16:12, John Hodrien wrote:
> On Wed, 5 Aug 2015, Graham Allan wrote:
> 
>> That's an interesting question - to clarify, if you have an automated
>> "yum update" going on, and the nvidia drivers get updated, does that
>> imply the currently-running system is destabilized, or do you just
>> mean (as I always assumed) you simply have to reboot to get the new
>> version active.
> 
> Definitely destabilised.  You can find that a log out can cause X to die
> and
> not come back if you update the driver without a reboot.
> 
> I'd always put off updating unless you're in a position to reboot right
> now,
> as you'll get warning messages too about the driver not matching, even
> if you
> don't obviously see problems.
> 

Agreed, it's best to schedule the update for a time when it's convenient
to also perform a reboot for the reasons John gives above.

The main issue is that the kernel driver and Xorg lib versions must
match. The kernel module is loaded at boot and will remain loaded
whereas the Xorg libs are loaded as X start so if a user logs out,
subsequent attempts to login will fail as X will try to load the new
libs whilst the old original kernel module is still loaded. This version
mismatch will prevent Xorg from starting. In theory it should be
possible to remove and reload the kernel module but in practice it is
nearly always easier to reboot.