Re: Laptop mode causing writes to wrong sectors?

From: Bart Samwel
Date: Thu Nov 17 2005 - 16:23:51 EST

Bradley Chapman wrote:
Mr. Samwel,

On 11/17/05, Bart Samwel <bart@xxxxxxxxx> wrote:
OK, that's the second report then. I'm beginning to worry. :/

Are you seeing any DMA timeout messages in your kernel log?

Once, when my /var partition got trashed - about thirty or forty loud
and scary messages from the IDE core saying that various disk accesses
(i.e. normal read/writes) were failing. I do believe DMA was

This could be the problem I was talking about. Was this happening during spindown or not?

Another time (i.e. just now), I got five Oopses in a row, most of them
in kmem_cache_alloc() but with one in generic_aio_file_read(). Unfortunately I am using fglrx right now so they are probably quite

I guess so. They all oops on reading the same address (0x05c2a5bb), there's something corrupted in the slab cache, cause unknown. Very possibly fglrx.

Most of the time though, I don't see anything.

...while still experiencing corruption?

Bradley, Jan, since when have these problems been happening? Kernel
version-wise, I mean?

They started with 2.6.13. I can't remember ever expereincing random
partition trashing or random file corruption in 2.6.12. I tried - that kernel did Bad Things as well.

So far though, as long as I stay on juice, 2.6.13 seems to behave.

Hmmmm. This means that you could still be experiencing the same thing that Andrea Gelmini was reporting. Could you try the things he said made it worse, and check if things go wrong? You are, of course, allowed to decline because of the risk involved. :-) The things are:

Big activity:

* iozone -A
* unrar big file
* In order to make it happen faster:
cd /proc/sys/vm
echo 100 > dirty_background_ratio
echo 1000000 > dirty_expire_centisecs
echo 100 > dirty_ratio
echo 1000000 > dirty_writeback_centisecs

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