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Re: pb with sheeva plug and usb/sd memory cards

Another intersting behaviour of the SD, USB and SSD also is the write
deadlocks :
see few attempts to get explain at my fastbench page [1].


[1] https://doukki.net/doku.php?id=wiki:tutoriels:fastbench

Le 24/08/2012 14:42, Laurent Lesage a écrit :
> Thank you all for your opinion and experiences.
> I confirm that I got nearly all the problems described by some of you :
> -some SD card work, some don't.
> -when they work, they have  slower access than USB sticks.
> -when they works, it happens that they suddenly become "read-only". The
> system continue to work but with lots of delays (of course, when the
> "disk" is RO, processes accessing the disk are "waiting" and the CPU
> uses more than 90% "waiting") - I don't know how it can continue worling
> but it does!
> -The sd card I could'nt restart finally works (I used another PC to
> write on it - it seems that the SD slot of my netbook is not that
> good.... I used an usb multifunction docking station for SATA/SD/MS, TF
> cards, and it seems to get better results when wirintg to SD cards).
> -I got a (not cheap) USB stick burned with the sheeva plug after a power
> outage. I got another one (a cheap one, not surprising) burned and
> terribly hot after a few days.
> I also read that there was a patch for the kernel to use the SD cards,
> but, as said, using the new DENX uboot, didn't make the things better -
> and this seems to mean that this "driver" is not good enough to rely on.
> As my sheeva is used as pbx, I must be able to rely on it. So I've
> bought a SATA SSD 32Go NAND flash disk and a box to connect it to USB.
> It is 2x the price but for 30 euros more, I should gain a few hours of
> time and have a really reliable system. I have systems running in Africa
> and it would be difficult for me to get the usb console from there... I
> will test the solution and I think I will change the usb keys on all the
> sheeva's running...
> I'll keep the list informed ...
> thanks again
> -- 
> Laurent Lesage
> DrEagle a écrit :
>> Le 23/08/2012 21:00, mick a écrit :
>>> On Wed, 22 Aug 2012 16:10:14 -0700
>>> Rick Thomas <rbthomas@pobox.com> allegedly wrote:
>>>> There have been persistent reports of flaky results with SD cards on
>>>> Sheeva (and other) Plug devices.  The best theory I've heard so far
>>>> is that the SD interface hardware/software in the Plugs is vey picky
>>>> about the specs and timing of the SD card interface.  Many people
>>>> have no problems for years, but if you happen to pick a card from a
>>>> slightly out-of-spec batch, you will have no end of intermittent
>>>> problems.
>>>> Why not just go back to using a USB flash stick?
>>>> Rick
>>> I had persistent problems with SD cards when I first bought a
>>> sheevaplug back in 2010. (See http://baldric.net/2010/03/30/unplugged/
>>> for example). My problems only disappeared when I moved to using a
>>> (powered) USB disk as boot and filesystem. 
>>> Mick
>> The master problem about SDHC/MMC is that the driver is a quick
>> adaptation of the Marvell U-Boot for denx u-boot.
>> It's not ported, nor maintained and not very tested by Marvell and
>> community.
>> I wrote it a few time ago to get the basic SDHC/MMC support into denx
>> u-boot, but the code is still buggy.
>> In my opinion, the mvsdio driver from Linux kernel might be ported to
>> denx to be mainline. I do not get it working for now...
>> The code for sdio driver from marvell u-boot was buggy and was just
>> ported without debugging.
>> It might work, might not.
>> The best method is to use NAND, USB stick are not fast enough and may be
>> broken also (I have a USB key drop unwritable after using it with a
>> sheevaplugs).
>> May be it is bug free now, with the latest git denx u-boot.
>> The IDE (SATA) for kirkwood from the git denx u-boot is now bugless and
>> fast enough to use in production with eSATA Sheevaplug and Kirkwood NAS
>> base.
>> ---
>> DrEagle

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