[PATCH v2] i2c-tegra: Use the suspend_noirq/resume_noirq not suspend/resume

On Thu, Sep 22, 2011 at 12:03:35PM -0600, Grant Likely wrote:

On Thu, Sep 22, 2011 at 11:51:32AM -0600, Stephen Warren wrote:

quoted

* Implement an explicit dependency management system within the kernel for
  device suspend/resume, such that I2C bus would not be suspended before
  the sound card that requires it. It is reported that Linus rejected this
  proposal since he wanted suspend ordering to be based on probe ordering.

This really should be revisted.  That was in the context of full
system suspend, but we're now in a world of runtime suspend which
absolutely does need dependency tracking or reference counting to get
the ordering right.

FWIW this was one of the bigger issues in the PM miniconference in Santa
Rosa, though a lot of the discission involved explaining the issues to
some of the x86 guys and there wasn't mssive progress on solutions.

quoted

* Enhance device probing such that the ASoC sound card device could defer
  its probing until all required resources were available. This would
  then cause the overall sound card suspend to occur at an appropriate early
  time. Grant Likely was reported to have been working towards this goal.

Yes, I'll send you my current patch for you to look at.  One of the
engineers from Linaro is going to be pushing that patch set forward.
However, I don't know if it helps with this problem because I believe
that the suspend order is based on the implicit probe order of
devices, but my patch allows drivers to cause the probe order to get
rearranged at runtime.  I don't believe there is a global list showing
the order that devices successfully got probed, but I may be wrong
here.

Yes, I'm not convinced it'll change anything here.  Though I guess it
should be a simple matter of programming to move devices around the list
depending on when they probe.