On Tue, 22 Oct 2019, Harald Dunkel wrote: > Hi Alan, > > On 10/21/19 7:48 PM, Alan Stern wrote: > > On Mon, 21 Oct 2019, Harald Dunkel wrote: > > > >> > >> The USB2 cable worked, too. Actually I had expected that the speed is > >> reduced automatically according to the specs of the card. ??? > > > > That is doubtful. The speed of the connection is determined when the > > connection is first set up. Unless the reader disconnects itself from > > the USB bus when a card is removed and reconnects when a card is > > inserted, the speed can't change. > > > : > : > > > > At any rate, it sounds like the 133x card is just too slow to keep up. > > > > > AFAIU the SD card is accessed similar to other block devices. There shouldn't > be any I/O errors on writing to a slow device, unless hardware or software are > faulty. The data to write is cached. > > Anyway, I got a new USB3 card reader today: No problem with it, even though > I wrote to the same slow SD card. Since the old SD card reader works OK using > USB2, I would either assume a bug in the XHCI driver for the old device, or a > hardware failure. > > Would you agree to this conclusion? Yes, except that I would go even farther. Since the same xhci-hcd driver works okay for your new card reader and the old card, I would rule out an error in the driver or the card. This means that the hardware/firmware in the old reader is most likely to be at fault. Alan Stern
