[Arm-netbook] microdesktop v1.7 arrived, works fine... but...

[Luke Kenneth Casson Leighton]

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crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68


On Tue, Apr 18, 2017 at 10:22 PM,  <doark at mail.com> wrote:
> On  Thu, 6 Apr 2017 06:12:16 +0100
> Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:
>> ok so the story goes like this:
>>
>> back in august 2016 i got the A20 card up and running with mainline
>> 4.7rc1 (or thereabouts), including patching in NAND support for a
>> proper mtd device.  it worked... up to a point... except when u-boot
>> did a complete scan it CORRUPTED the NAND flash... just from reads.
>>
>> i figured this was "just software" as it's pretty experimental, and
>> the 3.4.104 sunxi-nand works perfectly.
>>
>> fast-foward to a few months ago, when i was testing the external
>> micro-sd slot, weirdly it resulted in a kernel segfault *from the
>> sunxi-nand driver*.  i thought, "that's weird, might be to do with
>> current-fighting from the micro-desktop PCB not having level-shifting"
>>
>> sooo... that's now fixed: the micro-sd slot works perfectly through
>> the new revision 1.7 microdesktop's level-shifting IC.  however i got
>> exactly the same kernel segfault in the sunxi-nand driver, so i
>> temporarily took it out of the kernel config, tested again, and yes,
>> the micro-sd worked fine.
>>
>> ... except that when i booted it up again, the nand flash had been
>> corrupted.  now, bear in mind there's *NO DRIVER INSTALLED*.
>>
>> this is just too weird for me to deal with.  not to mention, because
>> of the age of the A20's Boot ROM there is now a limited set of
>> "legacy" NAND ICs available i've had it with them.
>>
> <snip>
>
> I'm sorry to hear you are having trouble.
> Personally, I like the super weird Linux problems. Can I have one of
> those malfunctioning alpha boards to try to figure out what's going on?
> I grant you that I've never worked on something quite this low level
> before, so I won't be solving it any time soon, but it would be worth
> looking into just so that we don't have this problem again (yes, I would
> like to learn how to create SBCs).

 sure - once i have working prototypes to replace it with.

l.