Hi Geert, On Monday 04 August 2014 13:28:32 Geert Uytterhoeven wrote: > On Wed, Jul 30, 2014 at 2:06 AM, Laurent Pinchart wrote: > > The third option would require storing the clocks lists in device drivers. > > I believe this is our best option, as a trade-off between simplicity and > > versatility. Drivers that use runtime PM already need to enable it > > explicitly when probing devices. Passing a list of clock names to runtime > > PM at that point wouldn't complicate drivers much. When the clocks list > > isn't SoC- dependent it could be stored as static information. Otherwise > > it could be derived from DT (or any other source of hardware description) > > using C code, offering all the versatility we need. > > > > The only drawback of this solution I can think of right now is that the > > runtime PM core couldn't manage device clocks before probing the device. > > Specifically device clocks couldn't be managed if no driver is loaded for > > that device. I somehow recall that someone raised this as being a > > problem, but I can't remember why. > > Perhaps you're thinking of clocks that were enabled (by the boot loader or > implicit reset state) before running Linux, and aren't disabled? That wasn't the reason, I know that clk_disable_unused() takes care of that problem (provided the clock drivers behave correctly, the commit you mention below shows that's not always the case, but that's an unrelated issue). > That was fixed by commit bb178da701382a230e26d90cf94e8a24b280e0d9 > ("clk: shmobile: mstp: Fix the is_enabled() operation"). -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html