Some more tests: - disabling LPAE has no effect, same hang after few minutes - attempting to use 2GB MLO/u-boot on new 4GB board makes it very unstable (crashes or hangs early while booting the kernel)
On Tue, Oct 2, 2018 at 6:29 PM Michael Mrozek EvilDragon@openpandora.org wrote:
ideas:
- perhaps the problem has something to do with idle/power saving. Need
to check if there are RAM registers related to that. Does anyone know if it currently tries to do RAM self-refresh while idle?
Hm, but would idle / power saving trigger when the system is doing something? Because when doing my test runs, I always run a script that spits out the voltages, temperatures and remaining temperature left every 10 seconds.
And what does it do in between those 10s? If the system has no work for any periods, even as short as 1ms, it's called idle and power saving mechanisms start.
So Linux doesn't really idle around, but freezes anyways after some minutes. And sometimes it even freezes while booting - and it's anything but idle there.
It can be partially idle while booting, for example CPU can have nothing to do while data is arriving from the SD card (data is copied to RAM by SD card controller and CPU is not used). And because it is some important data, like loading systemd itself, kernel would have no other process to run and would put the CPU on idle for a short while.
- See if a non-LPAE-Kernel has a different effect
no
- Boot the kernel directly into a shell (without loading any other drivers except for the ones directly included in the kernel). Test whether this runs more stable and then modprobe the remaining drivers one after the other. After all, Tony was running the memtest similar as well, and that didn't fail.
Yeah that's something to try. Perhaps just move /lib/modules somewhere so they don't autoload (not sure if they go to the ramdisk currently).
On Tue, Oct 2, 2018 at 8:54 PM H. Nikolaus Schaller hns@goldelico.com wrote:
And I had a bad setup on one SD card some days ago for the LC15-eval board. This repeatably triggered a Freeze ca. 3 seconds into boot time (last messages were that LDO.8 and LDO.5 were initialized). The RESET button was responsive up to ca. 0.1 seconds before that, but not after.
I've seen such behavior too, it all just becomes super-unstable for no reason, and it persists resets. I then have to remove the battery for some time to recover, and then it comes back to hang-in-a-few-minutes mode. This is without changing anything on the SD card. Really hard to make any sense from all this.
GraÅžvydas