Comments on DINGUX: SHOWSTOPPER

@sverox: Yes, because even if the corruption only ...

2009-08-05T16:53:13.956+02:00

@sverox: Yes, because even if the corruption only appears where the writes are supposed to be, then at some point he will have to write in the "file allocation table". And if that write corrupts, then a lot of files (if not all) will be damaged promptly. But it could also be (I have no idea) that corrupted writes happen at the wrong position, then every single write (even if it is only such a small operation as changing the "last access" time of a file) can corrupt the complete file system

Hello , is this problem effects other files on SDc...

2009-08-05T15:04:48.336+02:00

Hello ,
is this problem effects other files on SDcard. Mean files outside local directory.
I have roms and videos in other direcotries in root of SD - is they become corrupetd soon or later.

Now that I read your comment again, I see that wha...

2009-08-03T23:20:20.734+02:00

Now that I read your comment again, I see that what I said makes no sense. The pages are much smaller than 256KB

Booboo, now that you say it happens at page bounda...

2009-08-03T23:13:15.599+02:00

Booboo, now that you say it happens at page boundaries with a fixed max size: I remember the rockbox port for sansa ams had a similar problem. They found out, that they can't write over a certain boundary (bank switch or whatever), but have to split up writes between those boundaries. Maybe currently the SD driver writes in "bursts" of 256KB each, and when a write happens right before a page boundary the stuff that is supposed to go after the boundary in the second page is put a the beginning of the first page.

@fanoush Tried already disabling DMA (using PIO)....

2009-08-03T17:12:31.290+02:00

@fanoush

Tried already disabling DMA (using PIO). The system crashes badly (not even kernel panic).

Also tried a slower clock to no avail.

The corrupted data looks like random data, though I must test further. Also the corruption always starts and ends at page boundaries and is a bit less than 256KB in size.

No wonder it corrupts the file system Just imagine that 256K burst of corruption includes the update of the FAT tables.

It can be anything. Slowing down mmc clock may hel...

2009-08-03T09:56:38.863+02:00

It can be anything. Slowing down mmc clock may help as well as turning off DMA in mmc code. I wonder if there is any pattern in the corruption (random bytes here and there or whole blocks) and what data is in the wrong places (random data, data that belongs to file just with bad offset,zeroes,...)

Exactly the same problem I had on Neo Free Runner ...

2009-08-02T22:21:47.385+02:00

Exactly the same problem I had on Neo Free Runner smartphone. It was solved by buying new fast and expensive SanDisk one.
And the second solution was kernel patch, which slowed down access speed for card. (I think googling for OpenMoko neo free runner kernel patches will help this problem to be solved)

Is it possible to do all the writing and saves sta...

2009-08-02T18:38:13.606+02:00

Is it possible to do all the writing and saves states or whatever to the built-in memory in the Dingoo? And use the SD card solely for storage of ROMs and media?

After further investigation, my Monkey Island 2 fo...

2009-08-02T10:11:50.642+02:00

After further investigation, my Monkey Island 2 folder engulfed the ScummVM folder... like, I opened up ScummVM and there were the files for Monkey Island 2. Also some data for Rise of the Triad was corrupted too.

I think I just had my first corruption. I was play...

2009-08-02T10:05:14.299+02:00

I think I just had my first corruption. I was playing around with ScummVM, and now I'm getting segmentation faults. It sucks, but I can still read the MiniSD, so I'll just back it all up and reformat.

I have run the tests and I got all three md5sum re...

2009-08-02T01:12:30.364+02:00

I have run the tests and I got all three md5sum results as being the same. It takes about 10 minutes or so to run:

# dd if=/dev/urandom bs=1M count=100 | tee test1.bin | md5sum
a3c7345f0d226169e1e0d3449c6379b1 -
# md5sum test1.bin
a3c7345f0d226169e1e0d3449c6379b1 test1.bin
# md5sum test1.bin
# cp test1.bin test2.bin
# md5sum test2.bin
a3c7345f0d226169e1e0d3449c6379b1 test2.bin

Don't worry booboo I'm sure you'll wor...

2009-08-01T23:57:04.402+02:00

Don't worry booboo I'm sure you'll work everything out ;)

Has anyone done the commands yet with a perfect re...

2009-08-01T21:09:01.670+02:00

Has anyone done the commands yet with a perfect result? I don't know how to do them, so I can't check.

@Andrew: If the Linux kernel encounters corruption...

2009-08-01T11:12:49.636+02:00

@Andrew: If the Linux kernel encounters corruption in the file system, it makes the mount read-only to prevent further damage. There should be a log message about it, check with "dmesg".

You can force the file system back to read-write using "mount / -o rw,remount" but doing so is dangerous of course. Until this bug is fixed, it's best to make sure you have no valuable files on the card unless you also have a copy elsewhere.

Booboo, I am still waiting for my Dingoo to arriv...

2009-07-31T18:20:36.717+02:00

Booboo,

I am still waiting for my Dingoo to arrive, but have been following your blog closely. I did a Google search for FAT corruption on microSD cards on Linux systems, and found a post on the gumstix mailing list listing a similar problem related to a bug on Marvell Controllers.

I know it is not the same hardware, but could give you a hint to solve the problem. The link is http://bit.ly/1aFrO1. Wish you luck!

Don't know if this helps but sometimes when I ...

2009-07-31T15:47:57.474+02:00

Don't know if this helps but sometimes when I connect the Dingoo to my Linux system it says the card is read-only. Others times it allows me to write to the card without any problems.

Don't be fooled if you have never experienced ...

2009-07-31T15:42:30.111+02:00

Don't be fooled if you have never experienced any problems. If savegames is all that you're writing to your miniSD you may have just been lucky.

If you really want to know if you're affected by this problem, execute the commands described in the post. That will move around about 200MB of data. In my case that guarantees some corruption AT LEAST OF THE FILES INVOLVED.

I get corrupted saves and configs sometimes too on...

2009-07-31T15:23:17.828+02:00

I get corrupted saves and configs sometimes too on my hama 2GB microSD, but most of the time everything works.

I have tried two different cards, with my micro sd...

2009-07-31T15:04:50.981+02:00

I have tried two different cards, with my micro sdhc kingston 8gb i get all kinds of problems. Files corrupted, deleted etc. My micro SD Sandisk 2gb is more reliable but after a while the card goes read only (no switch on the card), and i have to reformat it.

I haven't had a problem so far with my Transce...

2009-07-31T13:58:36.200+02:00

I haven't had a problem so far with my Transcend Micro-SD 8gb card with an adapter of the same kind, Class 6.

I'm able to save states on everything, includi...

2009-07-31T13:36:29.166+02:00

I'm able to save states on everything, including Snes9x and ScummVM. Seems like SD cards are the problem not the system. I have 2 gb card.

I seem to have more problems with my 8GB micro SD ...

2009-07-31T13:32:02.498+02:00

I seem to have more problems with my 8GB micro SD in mini SD converter than my 256MB mini SD - don't know if this helps you in narrowing down the problem.

@yt The problem is with low level sector writing ...

2009-07-31T12:41:41.719+02:00

@yt

The problem is with low level sector writing to the card, so it is independent of the file system used.

That said, you probably didn't noticed anything in ext2/ext3 because due to its internal structure it's more relsilient.

Ah - this would explain why I'm unable to save...

2009-07-31T11:59:06.001+02:00

Ah - this would explain why I'm unable to save any data since upgrading to the FAT32 kernel.

The EXT3 filesystem caused no problems previously.

At least I know I'm not going mad now!

For reference, my memory card is a Bytestor 4GIG Mini SHDC Class 4 .