Re: [PATCH] spi: qup: Fix incorrect block transfers

From: Mark Brown
Date: Wed Sep 24 2014 - 04:31:01 EST


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.

Attachment: signature.asc
Description: Digital signature