On Thu, Aug 24, 2006 at 09:37:39AM +0000, moreau francis wrote: > Russell King wrote: > > On Thu, Aug 24, 2006 at 08:44:25AM +0000, moreau francis wrote: > >> Mips one seems to be a copy and paste of arm one and both of them > >> have removed all APM bios stuff orginally part of i386 implementation. > > > > The BIOS stuff makes no sense on ARM - there isn't a BIOS to do anything > > with. > > I haven't said that it has been widely/wrongly removed... ROTFL! No, you were stating that the APM bios stuff was removed, and I gave the reason for it. Why are you now objecting to my explaination? > >> It doesn't seem that APM is something really stable and finished. > > > > It's complete. It's purpose is to provide the interface to userland so > > that programs know about suspend/resume events, and can initiate suspends. > > Eg, the X server. > > > > Is there something specific to ARM in this implementation ? I don't think > so and it's surely the reason why MIPS did copy it with almost no changes. MIPS copied it because presumably it was useful for them. > I understand that ARM implementation has been the first one but maybe now > why not making it the common power management for embedded system that > could be used by all arches which need it ? It could well become a common interface. But it is NOT power management infrastructure. It is merely a _userland_ interface. Nothing more. It does not do anything other than that. > BTW, why has apm_cpu_idle() logic been removed from ARM implementation ? This APM is just a userland interface. It has nothing to do with actual power management. CPU idling is handled entirely differently on ARM. > > The power management really comes from the Linux drivers themselves, > > which are written to peripherals off when they're not in use. The other > > power saving comes from things like cpufreq - again, nothing to do with > > the magical "APM" or "ACPI" terms. > > BTW why is it still called "APM" on ARM ? That's what the userland interface is called on x86. We could've called it apm_userland_interface_emulation_and_not_a_power_management_infrastructure.c but although that clearly states what it is, it would've been far too long a name. 8) -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core
