[elrepo] Problem with CUDA since 331.67.elrepo

[Phil Perry]

Hi Michael,

On 25/04/14 00:31, Michael Lampe wrote:
> They now have a second kernel module 'nvidia-uvm' that wants to be built
> and packaged too. Affected are both older CUDA versions and the new 6.0.
>

Yes, I noticed that module added a while back, but have yet to package 
it as I'm not a CUDA user and had no idea of it's intended usage nor 
facility to test. Now we have some real users here I'm happy to oblige :-)

> While that's easy to fix, there is an annoying little problem. There
> comes a new device file '/dev/nvidia-uvm' with the new driver module.
> And it picks an arbitrary unused major no. at load time. So you cannot
> have it loaded by modprobe automatically when the device node is
> accessed, because you cannot create the device node before the module is
> loaded, and you also cannot use udev in any way because this module
> creates no data in sysfs and therfore creates no udev events.
>
> But the usage pattern is that CUDA programs will access
> '/dev/nvidia-uvm' and expect everything to be already in place.
>
> The only solution I found is to piggyback the new module + device
> creation on the old one:
>
> $ cat /etc/modprobe.d/nvidia
> options nvidia NVreg_ModifyDeviceFiles=0
> install nvidia /sbin/modprobe --ignore-install nvidia; /sbin/modprobe
> nvidia-uvm; /bin/mknod -m 0600 /dev/nvidia-uvm c `/bin/grep nvidia-uvm
> /proc/devices | /usr/bin/cut -d' ' -f1` 0; /sbin/pam_console_apply
> /dev/nvidia-uvm
>
> This works because '/proc/devices' reveals what major the new module
> picked. Permissions are set and (automatically) maintained with the same
> logic that applies to the other /dev/nvidia* files.
>
> What do you think? If nobody comes up with a better idea, I'll post the
> complete patch.
>

A couple of questions here, to help me understand the options available 
to us.

Is this anything nvidia-modprobe can handle? Should we be packaging this 
file (I don't believe we are are present)?

I'd also like to review the rpmfusion package to see if/how the Fedora 
folks handle this.

I will need you guys, the folks that actually use this stuff, to guide 
me as to what you require and what works.

Thanks,

Phil