On Thu, 20 Aug 2020 21:03:11 +0200 Boris Brezillon <boris.brezil...@collabora.com> wrote:
> On Thu, 20 Aug 2020 18:16:14 +0000 > Parshuram Raju Thombare <pthom...@cadence.com> wrote: > > > >Hm, not sure that qualifies as a fix. The current implementation was > > >correct, it was just reserving a slot in the device table for devices > > >that didn't have an init address or on which SETDASA failed. > > If I3C controllers like ours use hardware slots to store slave devices > > info, > > due to limited available slots this can cause issue. > > If some slots are lost due to > > 1. only init_dyn_addr and no static_addr in DT > > OR > > 2. SETDASA failed > > Well, having a slot with a static address is valid, though I agree > it's not really useful. > > > at the end of DAA some devices may be left without dyn_addr allocated from > > master > > and hence can't work properly. > > My point is, there's no address or device slot leak, it's just that > reserving a slot for I3C devices that only have a static address is > kind of useless. But let's be honest, given the number of I3C devices > available out there, I don't think it will hurt us before quite some > time :P. That's not to say we shouldn't address that, I just don't > think it deserves a Fixes tag. > > > I think during our discussion we recognized this change as a bug. > > IIRC, I was talking about the first patch in the series. > > > That is the reason I added fixes tag, but if you think otherwise I can > > remove this tag. > > > > >> -static void i3c_master_pre_assign_dyn_addr(struct i3c_dev_desc *dev) > > >> +static int i3c_master_pre_assign_dyn_addr(struct i3c_master_controller > > >> > > >That function now does more than just assigning a dynamic address: it > > >also creates the i3c_dev_desc. It should be renamed accordingly > > >(i3c_master_early_i3c_dev_add() maybe). > > Ok > > > > >You should reserve the address before calling > > >i3c_master_pre_assign_dyn_addr(): > > > > > > /* > > > * We don't attach devices which are not addressable > > > * (no static_addr and dyn_addr) and devices with > > > * static_addr but no init_dyn_addr will participate in DAA. > > > */ > > > if (!i3cboardinfo->init_dyn_addr || > > > !i3cboardinfo->static_addr) > > > continue; > > Don't we want to cover the case when only init_dyn_addr is present ? > > Uh, yes, my bad. > > > I am not sure if we can't have init_dyn_addr without static_addr. > > You can, when you want to assign a specific dynamic address to a device > that doesn't have a static address (see the 'try to assign init_addr > dance' in i3c_dev_add()). > > > May be what we need is > > if (!i3cboardinfo->init_dyn_addr) > > continue; > > > > ret = i3c_bus_get_addr_slot_status(&master->bus, > > i3cboardinfo->init_dyn_addr); > > if (ret != I3C_ADDR_SLOT_FREE) { > > ret = -EBUSY; > > goto err_rstdaa; > > } > > > > i3c_bus_set_addr_slot_status(&master->bus, > > i3cboardinfo->init_dyn_addr, > > I3C_ADDR_SLOT_I3C_DEV); > > > > if (i3cboardinfo->static_addr) > > i3c_master_pre_assign_dyn_addr(master, i3cboardinfo); > > Yep, that's correct. > > > IMHO this is functionally same to what I sent. Just that init_dyn_addr is > > reserved before, > > and we leverage the change in reattach to bypass failure due to second > > attempt > > to get init_dyn_addr in reattach called from > > i3c_master_pre_assign_dyn_addr(). > > Unless I'm missing something, your solution didn't reserve the > init address when there's no static address, and we definitely want > that to happen, otherwise another device might steal it during DAA. My bad, it did. This being said, I find it much easier to follow when the reservation happens in one place, so I'm still in favor of the new version.