Every time I suspend or resume my laptop (Dell Latitude E6520, bought this year), I get 2 messages of the form displayed on the console just before shutting down/starting up:
[ 407.107610] ehci_hcd 0000:00:1d.0: dma_pool_free buffer-128, f6f18000/36f18000 (bad dma)
On occasion, I get a message of the form:
[ 3753.979066] do_IRQ: 0.177 No irq handler for vector (irq -1)
On occasion, my machine freezes with a flashing Caps Lock button when suspending, after which I need to do a hard shutdown. This never happened before the messages started appearing (a while back), and I think it never happens without a do_IRQ message appearing (although I'm not sure about that). [There's nothing in the owner's manual on a flashing Caps Lock button; apparently it may be a kernel panic if the scroll lock also flashes, but the laptop doesn't have a scroll lock light, and there's no message on the console saying kernel panic.]
Are these bad DMA/do IRQ messages serious, and what can I do to investigate/troubleshoot them and the freezing?
Edit: I've also now received the following error messages a few times:
[246943.023908] JBD: I/O error detected when updating journal superblock for sdb1.
[246943.023958] Buffer I/O error on device sdb1, logical block 0
[246943.023996] EXT3-fs (sdb1): I/O error while writing superblock
Edit: Output of dmesg at http://pastebin.com/ra7MTQEj ; contents of /var/log/kern.log at http://pastebin.com/i6jf0Md9
Edit: the output of some smartctl (-a, -x, –log=error, –log=xerror) instructions is available at http://paste.ubuntu.com/1088488/ .
Edit (31/8/2012): Output of dmesg|grep -i ehci
available at http://paste.ubuntu.com/1177246/ .
Edit: (3/9/2012):Output of lshw is at http://paste.ubuntu.com/1183032
Best Answer
1. "Bad DMA"
Let's deal with the "bad dma" errors first, since they're the only consistent ones which are reflected in your logs.
Notice this tell-tale sequence, which repeats every time the "bad dma" errors occur:
cdc_ncm
module is implicated; this is a low-level USB interface to high-speed cellular modems2. "do_IRQ" and "sdb1"
It's harder to debug these isolated warnings without context (which can be the key, as shown above). So we'll just have to guesstimate until you can provide a
kern.log
containing one or both of these errors.Given that your SMART logs look OK, the "sdb1" errors probably come from even more USB communication issues with the external drive.
Again, I'd recommend trying one of the Quantal 3.5 kernels and seeings if things change, especially for the "do_IRQ".
3. Trying the 3.5-series Quantal Kernel (or a mainline build)
To install:
Reboot, and you should boot into the new kernel (check with
uname -a
). Nvidia/AMD graphics and Broadcom wireless cards may be problematic. You can always select your old 3.2-series kernel by keeping Shift pressed at boot until the Grub menu shows, and then going into "Previous Linux Versions"For even more bleeding-edge kernels, you can try one of the mainline builds. Please see this question and answer for more information: