Re: [dpdk-dev] [PATCH] [RFC] ether: standardize getting the port by name

["Gaëtan Rivet" <gaetan.rivet@6wind.com>]

On Thu, Nov 30, 2017 at 10:44:58PM +0100, Thomas Monjalon wrote:
> 30/11/2017 22:21, Stephen Hemminger:
> > On Thu, 30 Nov 2017 18:35:11 +0100
> > Thomas Monjalon <thomas@monjalon.net> wrote:
> > 
> > > 30/11/2017 18:15, Stephen Hemminger:
> > > > Some thoughts.
> > > > 1) Not all devices are PCI; look at recent VMBUS  
> > > 
> > > Yes, we need a syntax which works for every devices.
> > > I suggest to use the prefix "pci:" before the PCI id.
> > > We need also a prefix and ids for NXP buses.
> > > We could use "vmbus:" before VMBUS ids.
> > > How VMBUS ids look like?
> > > 

rte_devargs are easily accessible, user-readable. Only thing missing
would be requiring a 1-1 mapping between an rte_devargs and a port, thus
requiring PMDs to have at least one version of a device string that
would probe a single port (as is done with port= in mlx4).

Implementing an rte_devargs to rte_device in rte_bus is simple enough,
and this would allow implementing an rte_devargs to port_id in rte_eth.

What am I missing?

> > > > 2) The name may have to be set before MAC address is determined on boot.  
> > > 
> > > I don't understand this comment.
> > > Do you mean MAC may be unknown when starting DPDK?
> > 
> > The MAC be known by the hardware, but the device would have to be
> > created before using  hardware to read it.
> 
> Indeed, it is a problem if we want to use this syntax for blacklist.
> 
> 
> > > > 3) The names themselves are not persistent or human friendly. This is hard
> > > >    see the effort udev goes to.  
> > > 
> > > Yes udev has a syntax to identify devices. It can be inspiring.
> > > Qemu may also be inspiring:
> > > 	https://github.com/qemu/qemu/blob/master/docs/qdev-device-use.txt
> 

-- 
Gaëtan Rivet
6WIND