Похоже после обновления ядра, появилась ошибка при подключении usb флэшек
Sep  9 18:56:57 localhost kernel: [ 2843.394010] sd 7:0:0:0: [sdb] No Caching mode page present
Sep  9 18:56:57 localhost kernel: [ 2843.394018] sd 7:0:0:0: [sdb] Assuming drive cache: write through
Sep  9 18:56:57 localhost kernel: [ 2843.398002] sd 7:0:0:0: [sdb] No Caching mode page present
Sep  9 18:56:57 localhost kernel: [ 2843.398011] sd 7:0:0:0: [sdb] Assuming drive cache: write through
Sep  9 18:56:57 localhost kernel: [ 2843.403031] sd 7:0:0:0: [sdb] No Caching mode page present
Sep  9 18:56:57 localhost kernel: [ 2843.403045] sd 7:0:0:0: [sdb] Assuming drive cache: write through

Такое на всех компах, где выполнил pacman -Syu