On Tue, Jun 07, 2011 at 05:48:17PM +0100, Frank Hofmann wrote: > There are a few dependencies this patch brings in: > > * due to the use of cpu_suspend / cpu_resume, it'll only apply as-is > to kernels no older than f6b0fa02e8b0708d17d631afce456524eadf87ff, > where Russell King introduced the generic interface. > Patching these into older kernels is a little work. > > * it temporarily uses swapper_pg_dir and establishes 1:1 mappings there > for a MMU-off transition, which is necessary before resume. > In order to tear these down afterwards, identity_mapping_del() needs > to be called; for some reason that's #ifdef CONFIG_SMP ... > > * it needs to "catch" sleep_save_sp after cpu_suspend() so that resume > can be provided with the proper starting point. > This requires an ENTRY(sleep_save_sp) in arch/arm/kernel/sleep.S so > that the symbol becomes public. > > * it assumes cpu_reset will disable the MMU. cpu_v6_reset/cpu_v7_reset > are currently not doing so (amongst some other minor chip types). > > * there's kind of a circular dependency between CONFIG_HIBERNATION and > CONFIG_PM_SLEEP, on ARM. The latter is necessary so that cpu_suspend > and cpu_resume are compiled in, but it cannot be selected via > ARCH_HIBERNATION_POSSIBLE because CONFIG_PM_SLEEP depends on > CONFIG_HIBERNATION_INTERFACE - selected by CONFIG_HIBERNATION. Another issue is that it uses PHYS_OFFSET in assembly code which is not permissible with P2V patching. _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
