Christian Hewitt <christianshewitt@xxxxxxxxx> writes: > Amlogic G12B and SM1 devices experience CPU stalls and random board > wedges when the system idles and CPU cores clock down to lower opp > points. Recent vendor kernels include a change to remove 100-250MHz > (with no explanation) [0] but other downstream sources also remove > the 500/667MHz points (also with no explanation). Unless 100-667Mhz > opps are removed or the CPU governor forced to performance, stalls > are observed, so let's remove them an improve stability/uptime. > > [0] https://github.com/khadas/linux/commit/20e237a4fe9f0302370e24950cb1416e038eee03 hehe, not a very helpful changelog in that khadas kernel commit :( > Signed-off-by: Christian Hewitt <christianshewitt@xxxxxxxxx> > --- > Numerous people have experienced this issue and I have tested with > only the low opp-points removed and numerous voltage tweaks: but it > makes no difference. With the opp points present an Odroid N2 or > Khadas VIM3 reliably drop off my network after being left idling > overnight with UART showing a CPU stall splat. With the opp points > removed I see weeks of uninterupted uptime. It's beyond my skills > to research what the cause of the stalls might be, but if anyone > ever figures it out we can always restore things. NB: This issue > is not too widely reported in forums, but that's largely because > most of the Amlogic supporting distros have been including this > change picked from my kernel patchset for some time. Very interesting. I've also noticed instability across suspend resume on VIM3/VIM3L and only got as far in debugging to noticing it was DVFS/OPP related, but didn't get much further yet. I'll give this a try to see if it helps. Thanks for finding & posting! Kevin
