On Wed, Apr 29, 2015 at 10:02:03AM -0700, Kevin Cernekee wrote:
On Wed, Apr 29, 2015 at 9:46 AM, Mark Brown broonie@kernel.org wrote:
We just need a single boolean?
Right, so if we add a per-regmap bool that tells us whether the device has been reset, then in the case of "not reset" we will have to write every regcache entry out to the device. Even the ones that weren't touched while in cache_only mode. This makes the "not reset" case much less efficient than the "reset" case.
The immediate point is to provide a useful external interface, the internal optimisation is much less urgent (and it's less clear to me how often we're going to need to do that at all - generally cache only and power loss go together.
BTW, any preferences on naming for the bool or for the renamed mark_dirty function?
Not urgently. Note that I'm *not* suggesting an immediate rename, that's definitely a separate change (which will be a lot more painful to merge due to cross tree issues).
i.e. regcache_sync() finds a register value marked "present". How do we know whether we need to write it back to the hardware? For the special case of "cached non default register values immediately after a HW reset" you can mostly figure this out, but if there was no HW reset how do we know which entries changed while the HW was inaccessible?
In the first instance do we care?
I'm not sure I understand the question.
Do we actually care about getting a list of the changed registers that much?