28.04.2020 11:01, Jon Hunter пишет: > > On 27/04/2020 16:18, Dmitry Osipenko wrote: >> 27.04.2020 18:12, Thierry Reding пишет: >>> On Mon, Apr 27, 2020 at 05:21:30PM +0300, Dmitry Osipenko wrote: >>>> 27.04.2020 14:00, Thierry Reding пишет: >>>>> On Mon, Apr 27, 2020 at 12:52:10PM +0300, Dmitry Osipenko wrote: >>>>>> 27.04.2020 10:48, Thierry Reding пишет: >>>>>> ... >>>>>>>> Maybe but all these other problems appear to have existed for sometime >>>>>>>> now. We need to fix all, but for the moment we need to figure out what's >>>>>>>> best for v5.7. >>>>>>> >>>>>>> To me it doesn't sound like we have a good handle on what exactly is >>>>>>> going on here and we're mostly just poking around. >>>>>>> >>>>>>> And even if things weren't working quite properly before, it sounds to >>>>>>> me like this patch actually made things worse. >>>>>> >>>>>> There is a plenty of time to work on the proper fix now. To me it sounds >>>>>> like you're giving up on fixing the root of the problem, sorry. >>>>> >>>>> We're at -rc3 now and I haven't seen any promising progress in the last >>>>> week. All the while suspend/resume is now broken on at least one board >>>>> and that may end up hiding any other issues that could creep in in the >>>>> meantime. >>>>> >>>>> Furthermore we seem to have a preexisting issue that may very well >>>>> interfere with this patch, so I think the cautious thing is to revert >>>>> for now and then fix the original issue first. We can always come back >>>>> to this once everything is back to normal. >>>>> >>>>> Also, people are now looking at backporting this to v5.6. Unless we >>>>> revert this from v5.7 it may get picked up for backports to other >>>>> kernels and then I have to notify stable kernel maintainers that they >>>>> shouldn't and they have to back things out again. That's going to cause >>>>> a lot of wasted time for a lot of people. >>>>> >>>>> So, sorry, I disagree. I don't think we have "plenty of time". >>>> >>>> There is about a month now before the 5.7 release. It's a bit too early >>>> to start the panic, IMO :) >>> >>> There's no panic. A patch got merged and it broken something, so we >>> revert it and try again. It's very much standard procedure. >>> >>>> Jon already proposed a reasonable simple solution: to keep PCIe >>>> regulators always-ON. In a longer run we may want to have I2C atomic >>>> transfers supported for a late suspend phase. >>> >>> That's not really a solution, though, is it? It's just papering over >>> an issue that this patch introduced or uncovered. I'm much more in >>> favour of fixing problems at the root rather than keep papering over >>> until we loose track of what the actual problems are. >> >> It's not "papering over an issue". The bug can't be fixed properly >> without introducing I2C atomic transfers support for a late suspend >> phase, I don't see any other solutions for now. Stable kernels do not >> support atomic transfers at all, that proper solution won't be backportable. > > > There are a few issues here, but the issue Thierry and I are referring > to is the regression introduced by this change. Yes this exposes other > problems, but we first need to understand why this breaks resume in > general, regardless of what the PCIe driver is doing. I will look at > this a bit more later this week. Let's postpone the reverting by 1-3 weeks then. Likely that there will be a proper (and trivial) solution by that time, otherwise it should be okay to revert the I2C patch.
