I did probably encounter this problem on TS7400. The system became
unstable after some time, mainly segfaults in shared libraries. It did
go away when i donloaded new TS image, which uses insmod -q -f
/sdcard.o -o sdcard0 dmaenable=0 in linuxrc.
Petr
On Fri, Aug 7, 2009 at 23:36, Doug<> wrote:
>
>
> Hi,
>
> We've been working on a project that uses the TS-7390 and we're finding a
> weird bug that is causing the SD card driver to get screwed up. I believe
> it's a bug in either the tsuart drivers or the tssdcard driver. I can
> reproduce the problem with a brand new SD card, after dd'ing the
> 512mbsd-latest.dd file from the TS FTP site to it (which contains the latest
> tsuart and tssdcard drivers).
>
> It seems that when reading simultaneously from ttts0 and the SD card, the SD
> card gets messed up and starts returning corrupt data whenever reading from
> it. The file system starts exhibiting strange behavior showing empty
> directories and incorrect file content, but the data on the card itself is
> fine once I reboot.
>
> If I rmmod tssdcard.ko and re-insmod it again, the problem is still there.
> After it happens I am no longer able to re-mount any file systems on the SD
> card.
>
> The problem does not show up when reading from the AMBA serial ports
> (ttyAM*). I haven't tested on any of the other FPGA serial ports, but I can
> confirm that the behavior occurs with ttts0.
>
> I have found a workaround--if the SD card driver is loaded with the
> parameter dmaenable=0, the problem never occurs. So I'm guessing this bug
> has something to do with DMA. If the problem has already occurred, I can
> actually unload the module and reload it with the dmaenable=0 parameter, and
> it works fine.
>
> The bug may not be obvious to see unless you drop the disk caches before
> doing every read operation on the SD card -- otherwise you may not notice
> the SD card is not working, because it's using a disk cache in RAM. To drop
> the caches, you do: echo 3 > /proc/sys/vm/drop_caches
>
> If you don't drop the disk cache, files you've already read (and the
> filesystem) will probably still show up okay. But if you try to open a
> different file after the problem has occurred, it will be messed up.
>
> If I open ttts0 without reading from it, the problem doesn't occur. It only
> happens when data is coming into the serial port and it is actually being
> read by a program, at the same time as SD card operations. I have uploaded a
> test shell script that attempts to reproduce the problem to the Files
> section of this group, using "cat" to read from the serial port. It's called
> "causeSDProblem"
>
> Boot from the SD card, put that file in /mnt/root, chmod +x it, and run it
> (I'd run it with the SD /mnt/root mounted read-only). It will sit there and
> display nothing. What it's doing is comparing the SD's version of itself to
> a copy of itself it stored in RAM over and over again. If it's sitting there
> doing nothing that means it's not finding any problems.
>
> As soon as you start externally sending data to the ttts0 serial port, the
> program will exit because either the read of itself failed, or the data it
> read was different from the original copy of itself that it read into RAM.
>
> Anyone else seen this happen? I am reporting it to TS and will refer them to
> this post, and figured this would be the best place to write this info down.
>
> Doug
>
>
--
Ing. Petr Ledvina
ekoTIP ID s.r.o.
identifikaÄnà technologie
Morseova 1126/5 30100 PlzeÅ
tel:608101056
www: ekotip.cz
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|