* H. Nikolaus Schaller hns@goldelico.com [181008 06:33]:
Hi,
Am 08.10.2018 um 05:09 schrieb Michael Mrozek EvilDragon@openpandora.org:
On Fr, 2018-10-05 at 07:49 -0700, Tony Lindgren wrote:
Hi,
hm, that is interesting. I tried to find out a bit about the DLL on the internet (as the memory datasheet simply says that it should never be disabled for production use), but the only I did find it this article about the BIOS setup: https://www.techarp.com/bios-guide/digital-locked-loop-dll/
The interesting: "However, the delay-locked loop circuit of every DDR, DDR2, DDR3 or DDR4 chip is tuned for a certain fixed frequency range. If you run the chip beyond that frequency rate, the DLL circuit may not work correctly. That’s why DDR, DDR2, DDR3 and DDR4 SDRAM chips can have problems running at clock speeds slower than what they are rated for."
That is indeed an interesting finding!
Yeah I agree that might explain why things hang at random if dll fails to lock coming out of self-refresh. And that would also explain the complete hang as DDR3 is not functional at all coming out of idle.
Regards,
Tony