[beagleboard] Re: SPI input is always 0 with BeagleBoneBlack Anstrom images


Thanks for posting this, I just got my Beaglebone Black last night, I'm new
to Angstrom and dts files so I've no real idea at the moment as to how to
actually use this information.

But I'm having a problem on the Pandaboard ES (various kernels) and
Beaglebone (3.2.23-psp18 ubuntu 12.04 rfs) where actually using the spidev
results in random (as far as I can tell) very long latencies in the spidev

I've posted test code:


that shows the problem, and includes some data for test runs on the PandaES
and original BB in the comments.

I use extensively the spidev on beaglebone to talk to an external peripheral.
I use ubuntu 12.10 with 3.8.x kernel.

I happened to take a scope plot of the spi transfers.
I would strongly agree there is something really bad going on with SPI.
I saw a small message of 100Bytes transfer takes around 100ms of time
to transfer.

Looks the problem is real.
I have not investigated but looks you are facing the same issue.