[RFC 0/1] New PCI Switch Management Driver

[Keith Busch]

On Mon, Dec 19, 2016 at 10:06:56AM -0700, Logan Gunthorpe wrote:
> As I noted, the hardware is compliant and works perfectly fine with the
> in-kernel driver. However, the hardware has many additional custom
> features that are not covered by the PCI specs. For example, it has an
> interface to count packets that match a specific criteria. It also has
> firmware that can be expanded to do completely custom things by the
> user. Additionally, the switch is _very_ configurable and has a
> configuration file that can be uploaded and downloaded.
> 
> All these features and more are exposed through a special management
> endpoint that is completely separate from the standard PCI switch
> interface. This work is a driver for that endpoint and is not required
> to use the switch. It only makes the advanced features available to the
> user.

Since the in-kernel driver binds to the device, won't this driver
conflict with the initialization the in-kernel one already does? Bus
master, MSI setup, etc?

Could you also provide the reasoning against making the functionality
this driver provides in user space?