Am Tue, 2 Oct 2018 14:39:28 +0300 hat Grazvydas Ignotas notasas@gmail.com geschrieben:
Hi,
I'm back and I've done some tests, no useful conclusions though. I have 2 4GB boards now, I'll call them old one and new one.
- the old board also hangs, although it seems to take much longer (3
hours at least)
- the new one hangs in minutes, but occasionally it can run for half
an hour or so
- u-boot tester doesn't fail on new one, although I haven't tried it
for too long (less than 10 minutes)
I've run them for half an hour without any issues, so yes, it doesn't seem to fail.
- memtester (on Linux) doesn't fail on new one, it also seems to allow
the new board to survive much longer. I think it survived overnight but hung later when I was at work.
THAT is interesting...
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. 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.
Or do you mean something else?
- try without any TILER patches. I can vaguely remember it was said
the TILER can't be used at all because of some errata, but Matt proved otherwise. Maybe with 4GB/LPAE the problem actually triggers.
I remember that (that's why it was so slow at the beginning), haven't found much about TILER in the errata though. Only one which doesn't seem to be too critical.
But it's a good idea trying that, yes. If someone compiles me a kernel, I'll test anything on various boards whatever ideas you have :)
I can't code much, but I can test.
Here's what I planned to do:
* See if a non-LPAE-Kernel has a different effect * 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.
Any other ideas or comments are very welcome :)
Gražvydas
On Mon, Oct 1, 2018 at 9:15 PM H. Nikolaus Schaller hns@goldelico.com wrote:
Hi Askarus,
Am 01.10.2018 um 19:45 schrieb Nino Bock askarus@openpandora.org:
Hello everyone,
in the forums EvilDragon said: "4GB RAM boards were working with only 2GB RAM enabled (as far as I remember - as that was the reason I ordered the RAM modules back then!)"
Did anyone with a 4GB Pyra try running it with only 2GB enabled?
Yes. We did that several times. Sometimes even unplanned (copying a non-LPAE kernel to the SD card).
Might it work if we only populate it with half the amount of RAM chips?
Unlikely. There are two separate busses from OMAP5 to 2 RAM chips each. So if one bus makes trouble it still will do if the other one is not used.
The only differences may be power demand and cross-talk.
These are important questions. If one of these options does actually work it will be fine for the first batch.
Of course it's better to fix things but we are at a state where we should start production as soon as possible. Either of these possibilities would bring some Pyras to life and be of no additional cost.
Maybe that's silly but if there is a chance that EvilDragon's memories are true, then for me it's obvious what to do.
BR, Nikolaus
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