I'm also experiencing this. In my case sdb happens to be the memory card reader. The output stops when I plug in a memory card. Here's an except from the dmesg output:
[ 1543.770351] sd 6:0:0:0: [sdb] 3970048 512-byte logical blocks: (2.03 GB/1.89 GiB) [ 1543.775577] sd 6:0:0:0: [sdb] No Caching mode page present [ 1543.775586] sd 6:0:0:0: [sdb] Assuming drive cache: write through [ 1543.780604] sd 6:0:0:0: [sdb] No Caching mode page present [ 1543.780611] sd 6:0:0:0: [sdb] Assuming drive cache: write through [ 1543.807961] sdb: sdb1 [ 2849.045190] sdb: detected capacity change from 2032664576 to 0 [ 2893.403941] sd 6:0:0:0: [sdb] 3970048 512-byte logical blocks: (2.03 GB/1.89 GiB) [ 2893.413063] sd 6:0:0:0: [sdb] No Caching mode page present [ 2893.413074] sd 6:0:0:0: [sdb] Assuming drive cache: write through [ 2893.418182] sd 6:0:0:0: [sdb] No Caching mode page present [ 2893.418190] sd 6:0:0:0: [sdb] Assuming drive cache: write through [ 2893.445548] sdb: sdb1 A similar bug has been raised at the kernel.org: https://bugzilla.kernel.org/show_bug.cgi?id=43190 ** Bug watch added: Linux Kernel Bug Tracker #43190 http://bugzilla.kernel.org/show_bug.cgi?id=43190 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/987993 Title: 'Test WP failed, assume Write Enabled' messages on console To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/987993/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs