On Tue, 2016-03-08 at 21:18 +0100, Bjørn Mork wrote: > Linus Torvalds <torva...@linux-foundation.org> writes: > > > > > So looking at this, I wonder... > > > > Why is that FLAG_LINK_INTR thing not just always used? > > > > The _only_ thing that FLAG_LINK_INTR does is to cause > > > > usbnet_link_change(dev, 0, 0); > > > > to be called after network device attach. That doesn't seem to be > > controversial. > Not all usbnet drivers support carrier detection, which is required to > ever bring the link up again. > > > > > Looking at some examples, we have ax88179_178a.c that doesn't set the > > flag, but instead does that usbnet_link_change() call at the end of > > ax88179_bind(). > > > > There are a few drivers that seem to never call that > > usbnet_link_change() at all, and don't have that FLAG_LINK_INTR flag. > > Would they break? > Yes. Drivers without carrier detection will be "down" forever. > > > > > Why is it called "FLAG_LINK_INTR" anyway? There doesn't seem to be > > anything "INTR" about it. > Beats me. I can only say that I always find naming difficult... > We could ask Ben, who introduced it in: [...]
It is supposed to imply that the device generates link-change interrupts. Of course it is also possible for a device driver to satisfy the requirement by polling the link state. Ben. -- Ben Hutchings Sturgeon's Law: Ninety percent of everything is crap.
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