Am Mittwoch, den 16.08.2017, 14:10 +0300 schrieb Grazvydas Ignotas:
Hi,
well this Samsung nomenclature is rather confusing. From what I understand: K4B8G1646D-MC* is DDR3 K4B8G1646D-MY* and K4B8G1646D-MM* is DDR3L. So you have checked the actual markings and they're -MMK0?
Yes. At least on the CPU Board I checked, they're all MMK0.
Tony's tests strongly suggest the chip wants full (not L) voltage for some reason. Could it be some of the samples sent were wrong? Can you check the markings on all 4G boards you have?
I will check them later. @Tony: Could you also check yours?
Other thing to check is the frequency, as it's DDR3L-1600 it should not be set over 800MHz.
Yes, I think Mathijs wanted to look at that, but didn't yet.
Another interesting thing from the datasheet: The normal temperature is 0-85C (or -40-85 for industrial part). There is also "extended" temperature range of 85-95C which is supported, but requires refresh commands to be doubled in frequency. I don't know if OMAP5 can do that...
Ah, okay! Well, we should add proper throttle values into the DT file anyways. I think the OMAP shouldn't go higher than 80C while using it.
Tony reported crashes went away with a heatsink, so it seems to be heat related too.
Gražvydas
On Wed, Aug 16, 2017 at 11:58 AM, Michael Mrozek EvilDragon@openpandora.org wrote:
On Mi, 2017-08-16 at 10:20 +0200, Michael Mrozek wrote:
AAhh - I think I found my problem! I'm plain stupid!
That Samsung guide SAYS we have the low-power-version: http://www.samsung.com/semiconductor/global/file/resourceMgmt/2016/ 11/D DR3_Product_guide_Oct.16[2]-0.pdf
K4B8G1646Q-MMK0 IS 1,35V:) Industrial Temp.( -40C ~ 95C) & Low VDD(1.35V)
On first glance I saw the interface voltage, which is 1,5V.
Well... then it could be noise, though hopefully it isn't, as it would increase power consumption a lot!
On Mi, 2017-08-16 at 09:42 +0200, H. Nikolaus Schaller wrote:
Okay... it gets even more weird now.
Here is the K4B8G1646D as DDR3 (1,5V) variant: http://www.samsung.com/semiconductor/global/file/product/2016/06/ DS_K 4B 8G1646D_MC_Rev1_0-0.pdf
Here you can find it as DDR3L-variant: http://www.samsung.com/semiconductor/global/file/product/2016/03/ DS_K 4B 8G1646D-MY-M_Rev09-0.pdf
(this one explicitely says our ordered K4B8G1646D-MMK0 is DDR3L which supports 1,35V)
Then there is this product guide from Samsung: http://www.samsung.com/semiconductor/global/file/resourceMgmt/201 6/11 /D DR3_Product_guide_Oct.16[2]-0.pdf
Which basically says our chip is DDR3 with 1,5V.
According to our distributor, the chip we ordered and received should be DDR3L.
So... anyone has any idea what's wrong here? :O
Hi, according to my data sheets the K4B8G1646D is the DDR3L and the K4B8G1646Q isn't.
So please someone double-check before moving around chips&money.
So it is not the wrong chip but it might be too much noise on the data/clock/etc. which doubles for a dual-die/dual-chip-select chip. This gets better margin when increasing voltage levels.
Am 16.08.2017 um 09:32 schrieb Michael Mrozek <EvilDragon@ope npan do ra.org>:
Okay... Now we have a bit of a problem.
Apparently,.as the memory was basically working but just freezing (we we thought was a software issue), we've ordered the memory already - we have 4000 of those chips in stock.
I'm now trying to find our whether we can exchange them (they're still untouched and sealed), but this might not work...
What downsides do we.have with DDR3 memory? How much more power.do http://power.do/ they consume? How much more.heat do they produce?
ignoring non-linear effects: (1.5V/1.35V)^2 = 1.23 i.e. 23% more.
Are there any other downsides?
A tiny one: we need separate DTB for 2GB and 4GB... But U-Boot can load the right one since we already have two different U-Boot binaries.
BR, Nikolaus
On August 16, 2017 2:29:37 AM GMT+02:00, Michael Mrozek <EvilDragon @openpandora.org> wrote: On Di, 2017-08-15 at 17:00 -0700, Tony Lindgren wrote:
I just checked the part number on the 4GB RAM chips - and indeed, it is the K4B8G1646D, which means we have the DDR3 and NOT the DDR3L version (which would be K4B8G1646Q).
That's the reason we need 1.5V here. So we got the wrong memory chips for our use case!
I'll check back with what we ordered and what we received.
- Tony Lindgren tony@atomide.com [170815 16:57]:
Somehow we need 1.50V for the 4GB DDR3 to work reliably. No idea so far why this is though.
And here's the related kernel dts change for 1.50V.
Tony
8< ----------------------- From tony Mon Sep 17 00:00:00 2001 From: Tony Lindgren tony@atomide.com Date: Tue, 15 Aug 2017 13:06:47 -0700 Subject: [PATCH] ARM: dts: Fix up DDR3 voltage for pyra 4G
Looks like we need 1.50V instead of 1.35V for pyra-4g DDR3 to work reliably. Note that this needs to match the voltage configured by the bootloader.
When testing memory with two instances of memtester 1900M for example, make sure ti-soc-thermal and thermal-generic- adc modules are loaded. You may also need to use a proper heat sink on the CPU board.
arch/arm/boot/dts/pyra-mainboard-v5.0.dtsi | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/arm/boot/dts/pyra-mainboard-v5.0.dtsi b/arch/arm/boot/dts/pyra-mainboard-v5.0.dtsi --- a/arch/arm/boot/dts/pyra-mainboard-v5.0.dtsi +++ b/arch/arm/boot/dts/pyra-mainboard-v5.0.dtsi @@ -816,6 +816,12 @@ vbus-supply = <&otg_reg>; };
+/* pyra-4g memory needs 1.50V instead of 1.35V somehow */ +&smps6_reg {
- regulator-min-microvolt = <1500000>;
- regulator-max-microvolt = <1500000>;
+};
&smps10_out1_reg { /* never turn on or it may burn the Palmas! */ status = "disabled"; -- Mit freundlichen Grüßen,
Michael Mrozek
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