More on slow SD card

[Tony Baechler]

Hi all,

I have now ran several tests as requested here, both when the card reader was
very slow and when it was fast.  I have included the appropriate dmesg, lsusb
and typescript output.  When it is very slow, dd reports a read speed of 1
MBPS.  When it is acting normally, it's 19 MBPS.  You'll notice that in the
first dmesg file with the slow card, it says that the card was disconnected.  I
did not disconnect it.  That was something the kernel did on its own.  That was
with the 2.6.32 kernel.  I didn't try with 3.19, but based on previous tests, I
don't think it would matter.  You can download the various output files here:

http://batsupport.com/sdcard.tar

If I missed anything or if there are other tests you want me to run, please let
me know.  I'm still baffled as to why it would sometimes be slow and sometimes
not.  I think it has to do with the kernel somehow, but I'm not sure how.