On Thursday 21 June 2007, Pavel Machek wrote: > Hi! > > > > > IMO it can be done in two different ways: > > > > 1) via a .suspend() argument > > > > 2) via a global variable that the drivers can read. > > > > For sufficiently small values of "two" that is. > > > > Other solutions that have been described on the PM list include > > > > 3) Providing accessors to the information actually needed > > in drivers ... e.g. say whether this clock or power domain > > will be available in that target state. > > > > 4) Act more like "current" ... there's a function returning > > whatever "state" struct is settled on. (But ideally > > without the pseudo-global.) > > > > I'm amused that nobody really reacted to the technical comments in > > my previous posts on this thread. That's unfortunate, since from > > where I sit it feels to me like everyone else is a johnny-come-lately > > on this issue, and is now grasping at the quickest and dirtiest ways > > to work around the issue instead of coming to grasp with the various > > underlying issues. > > Well, rest of the word is still using PC here, so johny-come-lately > may not be completely unexpected. True. I could hardly escape noticing this problem though, given what it takes to get USB remote wakeup working on various systems. We've had a few years now to get that infrastructure in place. > Could you push framework for some embedded system you care about? OLPC > by chance? I'll probably push those two patches (clock core, AT91 implementation) since there seemed to be no objections. I don't work on OLPC. :) > > IMO #3 is strongly preferable. > > 3) actually looks ok to me. For acpi it would mean > > int acpi_state_we_are_entering(void) > > returning S1..S4, right? My original patch included acpi_get_target_sleep_state() returning ACPI_STATE_Sx values, yes. However, that was purely internal to ACPI-aware logic ... it was used to implement pci_choose_state(). Drivers would never make such ACPI calls themselves, they'd use pci_choose_state() instead. And the clk_must_disable() call is another instance of the same approach as pci_choose_state(): drivers getting access to the PM-reated information they need, without needing to use platform-specific calls or care about "what the target sleep state is". > > But I really thought the discussion on new PM methods, back a > > couple months now, was going to finally get rid of that. > > Umm, well, when someone gets to implement that... Oh. *THAT* little problem. Sorry, I thought it was in the works. - Dave - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
