On Debian 8, whenever I run after bootdmesg | grep error  I get[    1.226156] usb 1-4: string descriptor 0 read error: -22[    1.431774] EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro[    1.623611] usb 1-4: Direct firmware load failed with error -2[    1.628498] ath3k: probe of 1-4:1.0 failed with error -12[    1.773358] EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro,data=orderedCan anyone comment on these errors? It seems they do not affect the system (even if I suspect the boot to be slighter slow because of them)I do not know if this is a useful piece of information but I have powertop running at startup (all set to good).Edit1:Output of     lsusb -t    /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M    /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/9p, 480M        |__ Port 4: Dev 4, If 0, Class=Wireless, Driver=, 12M        |__ Port 4: Dev 4, If 1, Class=Wireless, Driver=, 12M        |__ Port 5: Dev 3, If 0, Class=Video, Driver=uvcvideo, 480M        |__ Port 5: Dev 3, If 1, Class=Video, Driver=uvcvideo, 480MEdit 2:I installed firmware-atheros now     dmesg | grep error is limited to    [    1.234204] usb 1-4: string descriptor 0 read error: -22    [    1.431215] EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro
dmesg errors: usb, EXT4, ath3k
boot
Lines 2 and 5 (both lines starting with EXT4): These lines only show mount options and no errors.Other lines: Use lsusb -t to find what device is causing the error - edit your question and add the output. Line 3 and 4 are most probably the result of the error from line 1.I expect this to be a bluetooth-related issue. Do you use bluetooth?Is the package firmware-atheros installed? Check with dpkg -l|grep firmware...https://packages.debian.org/de/jessie/firmware-atherosEdit, regarding your new two-line outputLine 1 Port 4: Dev 4, If 1, Class=Wireless, Driver=, 12M shows the device that causes the error and that no driver is loaded. Unfortunately, it doesn't provide a clue as to what device it actually is. If your system works as expected, just ignore the message.The second line still only shows a mount option and no actual error. You ignore it, it's a harmless piece of information.