On Thu, 15 Mar 2012, Grant Likely wrote: > On Wed, 14 Mar 2012 22:04:25 +0100 (CET), Guennadi Liakhovetski > <[email protected]> wrote: > > This patch adds a PM QoS requirement to the spi-bitbang driver, preventing > > the underlying SPI hardware driver to suspend for too long a time, as long > > as there are transfers on the queue. > > > > Signed-off-by: Guennadi Liakhovetski <[email protected]> > > Shouldn't this be part of the core spi infrastructure? Particularly since > queuing > is moving into the core.
Maybe, can you point me out to commit IDs / subject lines / archive threads? Anyway, this patch has to be reworked and extended. OTOH, if we universally agree, that no runtime-suspending of SPI controllers should take place with active CSs, it might happen, that we don't need this PM QoS at all - client drivers tend to hold CS lines for essentially longer periods of time, than what the SPI subsystem can recognise as a low-latency transfer sequence. The only example, that I can think of, where PM QoS could be useful is, if we have to keep latency low while communicating with different SPI devices on different chip-selects (like multiple audio-codecs, where their adjustment has to happen as synchronously as possible... No, I have no idea what I'm talking about:-)). Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ spi-devel-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/spi-devel-general
