On Fri, 4 Dec 2020 19:23:11 +0000 Vladimir Oltean wrote: > > > > What's the expected poll time? maybe it's not that bad to busy wait? > > > > Clearly nobody noticed the issue in 2 years (you mention lockdep so > > > > not a "real" deadlock) which makes me think the wait can't be that > > > > long? > > > > > > Not too much, but the sleep is there. > > > Also, all 3 of ocelot/felix/seville are memory-mapped devices. But I > > > heard from Alex a while ago that he intends to add support for a switch > > > managed over a slow bus like SPI, and to use the same regmap > > > infrastructure. > > > That would mean that this problem would need to be resolved anyway. > > > > So it's MMIO but the other end is some firmware running on the device? > > No. It's always register-based access, just that in some cases the > registers are directly memory-mapped for Linux, while in other cases > they are beyond an SPI bus. But there isn't any firmware in any case.
I see, so ocelot_mact_wait_for_completion() waits for some hardware engine to process the command? It looked like FW is hiding behind that register at a glance. 100ms sounds very high for hardware processing.
