On Mon, Nov 18, 2013 at 03:38:36PM -0700, Stephen Warren wrote: > 1) regcache_sync() doesn't mean "if the cache is dirty, flush the > dirty registers to HW", but rather, "if the cache is dirty, write any > registers that don't match HW defaults to HW". If the HW was in > cache-only mode because simply because clocks were turned off but not > power, then the register values were retained, and the current HW > register values may not be "HW defaults", and you may in fact /need/ > to write a value to HW that matches the HW default, yet is different > from the current retained register content. OK, that's a potential problem in general... Fortunately most of the uses actually cut power. > a) Make regmap creation read the initial HW state to use as HW > defaults when the regmap is created. IIRC, this is done for some > regmap configurations but not others. That said, this doesn't seem > correct, since there's no guarantee that the HW state when the regmap > is created /is/ the default HW state. Right, this is why we don't initialise the cache by default. > I think I still prefer option (c). there's also the option of doing an explicit read on that register to get it into the cache. But yeah, like I say I'm not totally against this and I did ack it already.
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