Hi.
Some days ago I tried to use my sdcard swap partitions (mmcblk1p2 - mmcblk1p3), both of 768 MB.
I installed flopswap on my n900 and, after some trouble with that program (thanks again sixwheeledbeast ), I finally activated the swap on sd.
But now I have a great stability issue.
In fact the system crash so often that I reverted to the internal swap.
My syslog says that is an I/O error, but I don't know how solve it.
Can you help me?

P.S. My sdcard is a 32 GB Sandisk sdhc uhs-I.
P.S.2 mmcblk1p1 is an ext4 filesystem, but the problem remains also if format it in fat32.
P.S.3 I've found these two threads about a problem with class 10 sdcard:
http://maemo.org/community/maemo-use...nd_corruption/
http://talk.maemo.org/showthread.php?t=72789
but it seems solved in newest kernels.

Edit:
Added a syslog reduced to the problem as suggested by Estel.

Little note for future - it is good practice to quote significant parts (or present them in separate file), while adding whole syslog just for refference - it's no fun to search through n thousands of lines, to find one you've described. What I mean, is presenting quote of things you see as important, + whole log as additional thing, in case you might be wrong about what's important
---

Anyway, about your problem - if you've tried recreating partition table/filesystems on that card from scratch, I can only advice testing different card (even 1GB or 2GB), to filter out possible cases. If other cards work ok, it's definitelly problem with that one - I'm using, personally, 32GB microSD (sandisk class 4), and I'm not experiencing it. Not that there are any technical reasons why there should be issues - even kernel thing you've described was about SDXC (64GB+) support, and as said, fixed in kernel power.

Also, as you noticed, other filesystems on microSD doesn't impact swap at all. It doesn't matter, for that purpose, if you're using ext4, vfat, or even swap itself, as /dev/mmcblk1p1 (first partition).

/Estel

to reinforce estel's comment, i have a 64gb sdxc class 10 uhs-1 card, formatted on device (have to reinsert to make it appear in file manager). partition 2+3 are 1gb swap, 1 is vfat. no issues what so ever since i started using it with kp51r1.

if your using ext4, i would look at tuning it during format. can't remember exact param but is something like -O^has_journal. this will disable journal, which although not quite as good for data integrity is usually much better for sd performance.

As suggested, I added a syslog reduced to the problem in first post.

I know that the filesystem of first partition doesn't impact swap, but I've also this problem http://talk.maemo.org/showthread.php?t=89619 so I wrote about ext4 only to prevent comment like "change filesystem to fat32".

The phone crashes normally when the written swap arrives around 80MB. I don't have any issue with sdcard on my pc and also on n900 when I normally use the first partition (except for the advised mounting problem).
However I'll try another sdcard as suggested by Estel.

Finally, I've tried with another sdcard.
Thanks to Estel, I can confirm that the issue is related to the sdcard.
In fact I don't have any problem with the other one (trascend class2 4gb).
There are on internet many post about issues with "card error 110 response 0x0 status 0x0". Generally they seems related to sdcard module error with newest sdhc.
I've found here also a solution, but I don't know how apply it:
https://bugs.launchpad.net/ubuntu/+s...ux/+bug/861668

P.S. I've also noticed that the problem is not related to the limit of 80MB, but it's more frequent when the n900 goes in stand-by or wakes up from it.

I forgot to say that, as suggested, I've repartitioned the card with a new partition table but without result.
Moreover, according to this thread (that involves my sd card - SanDisk Ultra UHS-I) the issue seems related to data timeout:
http://forum.xda-developers.com/showpost.php?p=33165459
The proposed solutions (by maemo.org ) are the same that I've suggested in first post, but looking better I noticed that the first one is in the cssu kernel (dto=14) and not the second.
Is it possible that my sdcard has a different dto that crashes my phone?

what do you need journaling for?
bragging?
simply use ext2
or disable journaling (hint: tune2fs)

i have a SanDisk 64GB uhs-1 with 2 ext2 partitions after a vfat one
and an extended partion with two swap partitions
don't use any of the "gadgets" to manage the swap,
simply swapon / swapoff every now and then...
no problemo

did you format it with ext4 as well?

I don't use anymore ext4, but only ext3.
However I have the problem also if I:
1) format the first partition in vfat (so it's not a problem of journaling);
2) use swapon/swapoff command
I've also checked the sdcard on pc with badblocks (read/write mode) and everything is fine.
Furthermore I've partioned the trascend card in the same way of the other one, so also here the first partition is ext3.

If I give:
the only difference between the cards is the address.
This is Trascend 4gb (good)
and this the Sandisk Ultra 32gb (bad)