Sorry - posted first as text + HTML. Re-posting as plain text.
Alan Stern wrote:
[Adding CC's, since this is a CPU power management issue just as much
as a USB issue.]
On Fri, 18 Sep 2009, Jan Holst Jensen wrote:
Hi.
I recently had severe problems with a new PC. When attaching an external
USB disk I would see USB resets once in a while in /var/log/messages and
after another while the disk would disconnect and data would be lost.
Like this
Sep 13 13:30:56 rumleskaft kernel: [164642.760290] usb 1-5: reset high
speed USB device using ehci_hcd and address 3
[repeated a number of times]
Sep 13 13:31:17 rumleskaft kernel: [164663.430421] sd 2:0:0:0: Device
offlined - not ready after error recovery
Sep 13 13:31:17 rumleskaft kernel: [164663.430459] sd 2:0:0:0: [sdb]
Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK,SUGGEST_OK
Sep 13 13:31:17 rumleskaft kernel: [164663.436193] usb 1-5: USB
disconnect, address 3
Sep 13 13:31:17 rumleskaft kernel: [164663.436446] sd 2:0:0:0: [sdb]
Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK,SUGGEST_OK
Sep 13 13:31:17 rumleskaft kernel: [164663.437711] lost page write due
to I/O error on sdb2
Sep 13 13:31:17 rumleskaft kernel: [164663.454184] lost page write due
to I/O error on sdb2
On my machine I found that disabling CPU C-states and forcing "GV3 only"
solved the problem completely. So in some cases it would seem that CPU
power management is causing timing issues (?). Can this be fixed in the
USB driver layer or does it take cooperation from the kernel's CPU power
management - or perhaps a combination of both ?
You can read more details about my issue at
http://www.fit-pc2.com/forum/viewtopic.php?f=26&t=851
Cheers
-- Jan Holst Jensen, Denmark
For what it's worth, I haven't heard of anything like this before and I
have no idea what the answers are. My guess is that a hardware bug is
responsible for the misbehavior while in higher C states.
Alan Stern
Could be. Hardware info for my system can be found at
http://www.jan-holst.dk/linux-usb/sysconfig.txt. It is the output of
/proc/version, /etc/issue and lshw.
-- Jan
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