Re: [PATCH 1/1] Add mkopci driver

[Arnd Bergmann <arnd@arndb.de>]

On Saturday 21 March 2015, Sergej Bauer wrote:
> Richard, thanks for your review.
> 
> But I still have several notes about driver:
> 
> > - You add new proc files, which is not really welcomed. Please consider sysfs.
> That will break a bunch of userspace applications, which use proc-files for several years (as long as from 2006
> year)
> 

> > BTW: Forgot to mention that this sounds like a job for UIO or VFIO.
> And again, you are right. But, again, there a number of applications wich use /proc/mkopci/core
> 
> But, of course, there may be decided that the kernel main line - this is not the place for such a driver. :)
> If the driver is suitable anyway, patch is at the end of this message

I don't think we should merge the driver with the proposed user interface. You can either
create a high-level abstraction for MIL-STD-1553, or use UIO or VFIO to provide a trivial
passthrough. In either case, both the ioctl interface and the procfs interface have no
future, and existing user space programs need to adapt.

There is nothing wrong with adding a driver for this hardware, but I'd rather see it done
properly than having an ad-hoc user space interface that was never reviewed publically
before it got used by applications.

	Arnd