Maximum amount of RAM for Loongson 2F

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Roman Mamedov

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Apr 21, 2011, 12:43:01 AM4/21/11
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Hello,

I am wondering what is the maximum amount of RAM supported by Loongson 2F.
I know 1GB is supported. But there are now also 2048 MB and 4096 MB sticks of
SODIMM DDR2-800 available for purchase. Should these work in Yeeloong/Fuloong?

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Roman

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项宇

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Apr 21, 2011, 1:20:01 AM4/21/11
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I know Lynloong(based on 2F) support 2GB@DDR2-667MHz.
but that may not work stably on Fuloong/Yeloong。


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ri...@happyleptic.org

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Apr 21, 2011, 4:03:15 AM4/21/11
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-[ Thu, Apr 21, 2011 at 01:20:01PM +0800, ?????? ]----

> I know Lynloong(based on 2F) support 2GB@DDR2-667MHz.
> but that may not work stably on Fuloong/Yeloong??

I got a fuulong upgraded to 2Gb without problem.

Roman Mamedov

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Apr 22, 2011, 9:45:21 AM4/22/11
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Thanks. :)

I now got a 4GB stick which has the following on its label:

Hynix KOREA 08
4GB 2Rx8 PC2-6400S-666-12
HMP351S6AFR8C-S6 AB

Looks like this:
http://www.nix.ru/include/view-photo.html?good_id=98390&pid=2254

Unfortunately I can't get it to work:

- The Yeeloong (PMON LM8089-1.4.9) does not power-up: when the power button is
pressed, it briefly turns on the power LED and the fan at a slow speed, then
while not displaying anything on the screen, just turns off after about 10
seconds.

- The Fuloong (PMON LM6004-1.3.6) when powered on displays the SiS video card
BIOS message, then after a long delay (maybe 10 seconds) it shows the full
screen Lemote logo; then after some seconds it gets to the PMON boot menu.
Looks like it works a lot slower than with its 512MB stick.
Then I select a kernel to boot (2.6.38.3), menu disappears, the HDD led
lights up for 2-3 seconds, then the LED turns off and nothing else happens
(no more LED activity, blank screen).

Is there anything I can try to make this work?

Looks to me it could be a PMON problem, but if so, are there newer PMON
versions than 1.4.9 (and were there changes for large RAM support in it)?

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With respect,
Roman

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ri...@happyleptic.org

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Apr 22, 2011, 10:22:33 AM4/22/11
to Roman Mamedov, loongs...@googlegroups.com
> I now got a 4GB stick which has the following on its label:
>
> (...)

>
> Unfortunately I can't get it to work:

I vaguely remember some discussions in the past about PMON problems
related to RAM upgrades. Can't offer much help unfortunately. :-(

Roman Mamedov

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Apr 22, 2011, 10:30:39 AM4/22/11
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No problem :)
But can you please tell which PMON version do you use (it can be checked in
kernel command-line, which appears in the beginning of "dmesg").
And which brand of 2GB RAM stick do you use (if you remember).

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Roman

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ri...@happyleptic.org

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Apr 22, 2011, 11:01:44 AM4/22/11
to Roman Mamedov, loongs...@googlegroups.com
-[ Fri, Apr 22, 2011 at 08:30:39PM +0600, Roman Mamedov ]----

> But can you please tell which PMON version do you use (it can be checked in
> kernel command-line, which appears in the beginning of "dmesg").
> And which brand of 2GB RAM stick do you use (if you remember).

Will check, but probably not until tuesday.

张福新

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Apr 22, 2011, 10:44:13 AM4/22/11
to loongs...@googlegroups.com, Roman Mamedov
The drive of 2f ddr pads are a bit low so that these machines have difficulty to support large memory,especially those with more than one rank modules. Carefully tuning the controller parameters for specified module can help,but it need some knowledge and skill and changes of pmon

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ri...@happyleptic.org编写:

>> I now got a 4GB stick which has the following on its label:
>>
>> (...)
>>
>> Unfortunately I can't get it to work:
>
>I vaguely remember some discussions in the past about PMON problems
>related to RAM upgrades. Can't offer much help unfortunately. :-(
>

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Roman Mamedov

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Apr 22, 2011, 12:50:45 PM4/22/11
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On Fri, 22 Apr 2011 19:45:21 +0600
Roman Mamedov <r...@romanrm.ru> wrote:

> - The Fuloong (PMON LM6004-1.3.6) when powered on displays the SiS video card
> BIOS message, then after a long delay (maybe 10 seconds) it shows the full
> screen Lemote logo; then after some seconds it gets to the PMON boot menu.
> Looks like it works a lot slower than with its 512MB stick.
> Then I select a kernel to boot (2.6.38.3), menu disappears, the HDD led
> lights up for 2-3 seconds, then the LED turns off and nothing else happens
> (no more LED activity, blank screen).

Hello,

I did some more experiments, and here's what I found so far.

1) PMON LM6004-1.3.6 does report all the RAM. It sets memsize=256,
highmemsize=3712, and shows 4 GB in the "BIOS setup" called via "main".

2) Starting memory test in PMON via "mt" runs for considerable time with no
errors.

3) Starting the "newmt" memory test fails immediately with a "TLB miss on
store" error: http://romanrm.ru/pics/2011/2011-04-22-fuloong-4gb-memtest.jpg

4) I managed to have the kernel start booting, by issuing
"highmemsize=256" (or even 768) in PMON, then loading the kernel. But it
fails very early at boot, it is tricky to read the messages there, but at
first it's "IRQ 14: nobody cared", then "Unable to handle kernel paging
request". I may try netconsole a bit later, though not sure if it will work
this early at boot.

5) Even when the kernel starts booting in the above manner, it is SLOW - I
can see how the text redraws and scrolls. So it confirms the delays before
PMON, with 4GB installed the machine (or the video card) runs very slowly
for some reason.

I do not think it is an electrical-level problem, because the above behavior
is completely consistent (everything happens 100% reproducible).

My wild guess: PMON cannot properly do a complete initialization of hardware
(IRQ, DMA?) because it is confused by this much system RAM. Maybe it can't map
some I/O area into below 4GB, when there are actual 4GB of RAM present?

I have noticed there is a 64-bit PMON branch available in the git repository
- how do I check if my PMONs are already compiled to 64-bit?

I need to decide pretty soon if I am going to return this memory stick to the
shop, so if anyone has ideas to try, don't hesitate to post ideas over this
couple of days... I think it'd be quite useful to find and fix the problem
with 4GB of RAM rather than just giving up on it, especially since it "almost
works".

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With respect,
Roman

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Roman Mamedov

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Apr 23, 2011, 9:09:09 AM4/23/11
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Thanks... also some more questions:
- which kernel version and please post your /boot/config-*
- does the RAM stick have 1 or 2 rows of chips on each side (i.e. 8 or 16
chips total).

Is anyone else successfully using 2GB of RAM in Fuloong? Please post your
details too. :)

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Roman

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Roman Mamedov

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Apr 24, 2011, 9:32:21 AM4/24/11
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On Fri, 22 Apr 2011 22:50:45 +0600
Roman Mamedov <r...@romanrm.ru> wrote:

> 5) Even when the kernel starts booting in the above manner, it is SLOW - I
> can see how the text redraws and scrolls. So it confirms the delays before
> PMON, with 4GB installed the machine (or the video card) runs very slowly
> for some reason.

This slowness is completely gone after changing from a 4GB stick to a 2GB one.

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Roman

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ri...@happyleptic.org

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Apr 26, 2011, 2:09:45 PM4/26/11
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-[ Fri, Apr 22, 2011 at 08:30:39PM +0600, Roman Mamedov ]----
> But can you please tell which PMON version do you use (it can be checked in
> kernel command-line, which appears in the beginning of "dmesg").
> And which brand of 2GB RAM stick do you use (if you remember).

Hum.
I remembered correctly having upgraded the RAM on the fuulong,
although now that I have opened the fuulong and removed the RAM
stick to take a picture of it, it occurred that it was only 1Gb and not
2Gb.
Sorry for the false hope. Like everything I say you'd better wait for
the facts check rather than trust my memories.


Roman Mamedov

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Apr 26, 2011, 2:39:32 PM4/26/11
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No problem, at least we now have the kernel issue with memory areas found
and patched. :)

I am going to look for a single-rank 2GB module to test, it seems they are
somewhat rare.

Also, does anyone know how to limit the kernel to using just 1GB of RAM from
2GB installed? I tried using the "memmap=1G$$1G"(double $ due to PMON seeing
a single $ as a variable reference) and "memmap=1G#1G" kernel parameters, but
they seem to be ignored. Did not check the source code yet.

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Roman

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ri...@happyleptic.org

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Apr 26, 2011, 3:03:19 PM4/26/11
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> Also, does anyone know how to limit the kernel to using just 1GB of RAM from
> 2GB installed?

I assume the simple mem=1G does not work as expected?

Roman Mamedov

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Apr 26, 2011, 3:10:18 PM4/26/11
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No, it just results in a lock-up.

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Roman

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