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?


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