[PATCH 0/8] sdhci: Move real work out of an atomic context

Andrew Morton akpm at linux-foundation.org
Wed Sep 8 08:38:13 EST 2010

On Wed, 14 Jul 2010 17:07:28 +0400
Anton Vorontsov <avorontsov at mvista.com> wrote:

> Hi all,
> Currently the sdhci driver does everything in the atomic context.
> And what is worse, PIO transfers are made from the IRQ handler.
> This causes huge latencies (up to 120 ms). On some P2020 SOCs,
> DMA and card detection is broken, which means that kernel polls
> for the card via PIO transfers every second. Needless to say
> that this is quite bad.
> So, this patch set reworks sdhci code to avoid atomic context,
> almost completely. We only do two device memory operations
> in the atomic context, and all the rest is threaded.
> I noticed no throughput drop neither with PIO transfers nor
> with DMA (tested on MPC8569E CPU), while latencies should be
> greatly improved.

This patchset isn't causing any problems yet, but may do so in the
future and will impact the validity of any testing.  It seems to be
kind of stuck.  Should I drop it all?

More information about the Linuxppc-dev mailing list