Re: [Xenomai] Add cards parameter to rt_e1000e module?

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On Fri, Dec 12, 2014 at 09:12:23PM -0500, Lennart Sorensen wrote:
> On Sat, Dec 13, 2014 at 02:03:58AM +0100, Gilles Chanteperdrix wrote:
> > I understand the need for the "cards" parameter, but...
> > Is not there another way to solve this issue ? I do not know,
> > something in /proc or /sys to tell Linux to not load this driver for
> > that card? I suppose if we tell Linux to not use its driver for some
> > cards, then later loading the rtnet driver will be used for these
> > cards? Adding the cards parameter means that the rtnet drivers
> > diverge from mainline drivers, and so imply a maintenance cost. On
> > the other hand, maybe that is a cheaper one than trying and solving
> > the issue globally.
> 
> Certainly a well behaved driver would not touch a device already handled
> by a linux driver.  It should be possible to just issue an unbind request
> to the linux driver for the desired device and then a bind request to
> the rtnet driver to take over that device.
> 
> But I have not looked at rtnet, so I don't know how those behave compared
> to linux drivers.

As all RTDM drivers, RTnet drivers are just linux drivers. The issue
is to have a setup where two cards with the same chip are used by
two different drivers. Linux does not have this problem, because it
rarely has several drivers for the same chip. The problem with the
bind/unbind solution is that the driver that will get all the cards
first depends on the drivers initialization order. With the "cards"
parameter, you do not have this issue.

-- 
					    Gilles.