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Author: Didier Kryn
Date:  
To: dng
Subject: Re: [DNG] How to stop udev from re-ordering devices
Le 23/06/2016 09:05, Simon Hobson a écrit :
> Rainer Weikusat<rweikusat@???> wrote:
>
>> >Reportedly, Linux hotplug already had the same problem.
> OK, that's what I'd have been seeing in the past then.
>
>> >During initialization, the kernel walks through the bus or busses it
>> >finds in order to locate all devices and enables them by calling the
>> >responsible driver init routines with information about the physical
>> >devices which were found. This means the names will be stable if all
>> >needed drivers are compiled into the kernel (in absence of deliberate
>> >sabotage by the drivers themselves).
>> >
>> >If there's no compiled-in driver for some device, a so-called hotplug
>> >event is generated
> Right. That explains a lot.
> So if the driver is built in then devices will be stable and determinate, if not then they won't. Which I guess means that a custom kernel with all drivers needed compiled in will have stable devices, but a general purpose one with loads of modules won't ? And as the vast majority of systems run generic modular kernels ...


     Hence the solution is simple: for random machine, edit udev rules 
to assign names according to the MAC address; for mass-production 
devices use a custom kernel with all drivers statically linked in the 
kernel. For disks, use UUID.


     Didier