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. 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. [0] https://github.com/khadas/linux/commit/20e237a4fe9f0302370e24950cb1416e038eee03 Changes since v1: - Split into two patches to allow for separate Fixes tags - Minor edits to commit messages for brevity and typos Christian Hewitt (2): arm64: dts: meson: remove CPU opps below 1GHz for G12B boards arm64: dts: meson: remove CPU opps below 1GHz for SM1 .../boot/dts/amlogic/meson-g12b-a311d.dtsi | 40 ------------------- .../boot/dts/amlogic/meson-g12b-s922x.dtsi | 40 ------------------- arch/arm64/boot/dts/amlogic/meson-sm1.dtsi | 20 ---------- 3 files changed, 100 deletions(-) -- 2.17.1
