USB card reader problem

[Tony Baechler]

I'm sending this again because I remembered something.  I have, in fact, 
tried the card reader on a different machine.  It didn't exhibit the odd 
behavior and the other machine was always on.  Also, I made note of the 
exact error message from kernel 2.6.32:

Cannot enumerate USB device on port 3

Doing a Google search, this would indicate a kernel issue, but as I 
mentioned, 3.19 does the same thing.  Another thing that's odd is sometimes 
when I plug in the card reader and boot the machine, the kernel doesn't see 
it at all.  If I unplug it and plug it in again, I get the above error but 
the kernel finds it immediately.  After it gives the error, it says device 
sdd found, assuming cache: write through.  I can always reproduce the very 
slow write speed after the error message and I almost never have the problem 
if the error message isn't displayed.

As another random piece of information, I installed kexec-tools and using it 
to reboot into the already running 2.6.32 kernel seems to not show the error 
even when the reader has been plugged in for several hours.

On 8/13/2015 2:29 AM, Petter Adsen wrote:
> On Thu, 13 Aug 2015 01:56:08 -0700
> Tony Baechler <bats at batsupport.com> wrote:
>> Is this a problem with my USB port, my card reader or some other hardware
>> problem?  Should I pass something on the kernel command line?  Other
>> external drives don't exhibit this behavior, but it happens on many
>> different SD cards.  For what it's worth, I've noticed brand new cards with
>> nothing on them seem to have the problem more often, but formatting them
>> sometimes helps.  Similarly, if I unplug the reader and plug it in again, I
>> get the strange error message and slow behavior.  I have two front USB ports
>> and it doesn't seem to matter which one I use.
>
> Do you have the option of trying the card reader in another machine,
> and/or trying another card reader on this machine? As a first instinct
> I would be suspicious of the reader, or maybe the cable, if other USB
> devices work fine.

Actually, this problem happened with my old card reader, so I replaced it, 
thinking that might be the problem.  The new reader seems better if I plug 
it in before the system boots, but otherwise there is no obvious difference. 
  The readers are different brands.  I don't have a different machine.  I'm 
not sure what cable you mean as the reader plugs directly into the USB port.