Errors in dmesg - Test WP failed, assume Write Enabled [duplicate]

Solution 1:

I'm having the same issue on the official 12.04 LTS relase i also believe it is causing the system to be less responsive. According to some sources it's harmless. (i can apparently only post 2 links)

The following thinks this is error output from an onboard card reader:

https://bbs.archlinux.org/viewtopic.php?pid=1059099

It's confirmed to be an upstream issue in

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/987993

Run lsusb and find the offending device

nathan@Ham-Bone:~$ lsusb 

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 0bda:0158 Realtek Semiconductor Corp. USB 2.0 multicard reader

In my case it's the Realtek multicard reader which a quick check of

$ dmesg | grep realtek
[    4.716068] usbcore: registered new interface driver ums-realtek
$ lsmod | grep realtek
ums_realtek            17920  0 

reveals a module ums-realtek

$sudo rmmod ums_realtek

Fixes the problem in a reversible way for me. That is

$sudo modprobe ums_realtek

enables the card reader again. I haven't tested if it works since I never use it.

If this doesn't work there are some other ways to disable usb devices by unbinding them in the /sys/ directory.

Solution 2:

I found that loading the driver with option ss_en=0 works. Doing

echo "ums-realtek ss_en=0" |sudo tee -a /etc/modules

makes the change permanent.

Further explanation:

While trying to discover why this message happens, I looked into the options for the two modules involved, ums-realtek and usb-storage. I did not feel that loading and unloading the ums-realtek module every time was a suitable solution, as I am often using the card reader.

Checking module options:

# modinfo ums-realtek 
  parm: auto_delink_en  enable auto delink (int)
  parm: ss_en           enable selective suspend (int)
  parm: ss_delay        seconds to delay before entering selective suspend (int)

Research into what these options were for did not yield any result, and I did not feel inclined to bother the author by email. Since this driver uses the usb-storage as well, I felt the "suspend" option might be enabled by default ( perhaps to conserve battery on laptops ) and the messages a result of wakeup-query-suspend sequences. Since I didn't care if the device was constantly powered on or not, I tried setting this option to 0 (off) and it works.