On Sat, Feb 25, 2017 at 7:19 PM, H. Nikolaus Schaller hns@goldelico.com wrote:
And what do you think about this?
... Sat Jan 1 06:07:45 UTC 2000 81° 82° 77° 31° 3826mV 1700MHz Sat Jan 1 06:07:46 UTC 2000 73° 74° 72° 31° 3805mV 1700MHz ^Ckill 2659 2660
root@letux:~#
A realistic explanation is that our DDR3 is a little more sensitive to noise by 1.5GHz operation than the EVM and hence we get the problems but don't see them on the EVM if it is more robust.
I had ruled out the DDR3 during my tests in November because the EMIF runs at the same speed, independently of the ARM core clock.
Therefore I thought there can not be an influence or problem. But if higher ARM load makes more noise on the DDR3 wires as well...
Wow very surprising indeed. When you found that DDR3 was severely undervolted and fixed it, it also became more stable and could handle higher frequencies, so it hinted that this was a DDR problem, but of course it was hard to make a connection back then...
We are really lucky Matt has found this, imagine the disappointment after the final boards arrive and would still be unable to run at 1.5GHz (well maybe they'd work without the sw fix, but I suspect they won't considering how we have everything crammed into such a small space).
This development made me unpack my board again hoping it would boot with all the fixes, unfortunately it doesn't, must be dead beyond hope. Even the board version detection is unstable on it:
U-Boot SPL 2016.11-01304-g918c4c4 (Feb 26 2017 - 00:12:35) OMAP5432-GP ES2.0 Trying to boot from MMC1 Found LC15 V5.5 board_mmc_init called (vers = 0) ERROR : check_gpio: invalid GPIO -1 <sometimes hangs here>
U-Boot SPL 2016.11-01304-g918c4c4 (Feb 26 2017 - 00:12:35) OMAP5432-GP ES2.0 Trying to boot from MMC1 Found LC15 V5.0 board_mmc_init called (vers = 50) MLO hard: gpio7 = eMMC soft: gpio32 = 0 (mmc1=eMMC) ctrl: gpio33 = 1 (ctrl=soft) mkimage signature not found - ih_magic = ea0000be Jumping to U-Boot loaded - jumping to U-Boot... <always hangs here>
Gražvydas