On Sun, Sep 20, 2020 at 11:33:41PM +0000, Vladimir Oltean wrote: > On Sat, Sep 19, 2020 at 04:43:28PM +0200, Andrew Lunn wrote: > > > > DSA only instantiates devlink ports for switch ports which are used. > > For this hardware, only 4 user ports and the CPU port have devlink > > ports, which explains the discontinuous port regions. > > This is not so much a choice, as it is a workaround of the fact that > dsa_port_setup(), which registers devlink ports with devlink, is called > after ds->ops->setup(), so you can't register your port regions from > the same place as the global regions now.
Correct. > So you're doing it from ds->ops->port_enable(), which is the DSA wrapper > for .ndo_open(). So, consequently, your port regions will only be > registered when the port is up, and will be unregistered when it goes > down. Is that what you want? I understand that users probably think they > want to debug only the ports that they actively use, but I've heard of > at least one problem in the past which was caused by invalid settings > (flooding in that case) on a port that was down. Sure, this is probably > a rare situation, but as I said, somebody trying to use port regions to > debug something like that is probably going to have a hard time, because > it isn't an easy surgery to figure the probe ordering out. I did intially create the port instances at the same time as the global ones, and it died a horrible death. And i was aiming to register a region for each port, not just those which are used. This splits into two problems. 1) Devlink has no concept of a port which is unused. We simply don't register unused ports. So we need to add a new devlink_port_flavour: DEVLINK_PORT_FLAVOUR_UNUSED. That seems easy enough. 2) We need to rearrange the order the core sets stuff up, such that it registers devlink ports before calling the DSA driver setup() method. I think that is possible after a quick look at the code. Andrew