[PATCH] spi: qup: Fix incorrect block transfers

Mark Brown broonie at kernel.org
Wed Sep 24 01:30:35 PDT 2014


On Tue, Sep 23, 2014 at 02:26:13PM -0500, Andy Gross wrote:
> On Tue, Sep 23, 2014 at 12:24:27PM +0300, Ivan T. Ivanov wrote:
> > On Sun, 2014-09-21 at 23:27 -0500, Andy Gross wrote:

> > > This patch fixes a number of errors with the QUP block transfer mode.  Errors
> > > manifested themselves as input underruns, output overruns, and timed out
> > > transactions.

> > At what speeds are you seeing those errors?

> We've tried 25MHz and 50MHz.  Both fail in the same way.  Keep in mind this is
> definitely a timing / race issue and it probably also dependent on the latency
> of the attached device.  I cannot reproduce this at all on my IPQ8064 based
> board, but others can.

With SPI everything is entirely clocked from the master - the attached
device can't cause any of those issues unless there's an electrical
problem that *really* upsets the master.
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