ubuntu 安装后遇到[sdb] Asking for cache data failed Assuming drive cache: write through

原文地址：http://blog.csdn.net/liufei_learning/article/details/8521221

在安装的ubuntu12.10 64bit server时，出现下面的错误：

[11690.011238] [sdb] Asking for cache data failed

[11690.011248]  [sdb] Assuming drive cache: write through

googel了下找到下面的解决方案，是ubuntu的一个bug：在我机器上卸载后就没有问题了，但是重装就会有问题，临时的解决办法时，写一个脚本开机运行

sudo rmmod  ums_realtek
http://askubuntu.com/questions/132100/errors-in-dmesg-test-wp-failed-assume-write-enabled

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 hubBus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hubBus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 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 realtekums_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.

7down voteaccepted

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 hubBus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hubBus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hubBus 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 realtekums_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.