On 09/24/08 18:59, Bill Holler wrote: > On 09/24/08 18:45, Li, Aubrey wrote: > >> Bill.Holler wrote: >> >> >> >>> A callback will work great. The callback interface is in >>> uts/common/sys/callb.h. We can add a callback class such as >>> #define CB_CL_CPU_DEEP_IDLE 16 >>> >>> cpudrv can register a CB_CL_CPU_DEEP_IDLE callback >>> in its init function. >>> /dev/pm can invoke callb_execute_class() CB_CL_CPU_DEEP_IDLE from its >>> ioctl case. >>> >>> The cpudrv callback can do whatever it needs to do to enable/ >>> disable C-States. The cpudrv callback can call the hpet >>> interface to enable/disable the cstate_timer. >>> >>> >>> power.conf >>> | >>> v >>> pmconfig >>> | >>> v >>> pm driver's pm_ioctl >>> callb_execute_class(CB_CL_CPU_DEEP_IDLE) >>> | >>> v >>> cpudrv callback function >>> | ^ >>> v | >>> hpet.cstate_timer_[enable|disable] >>> >>> >>> >>> I believe there will be only 1 callback into cpudrv, not >>> 1 callback per driver instance? >>> >>> >>> >> I think so for hpet timer enable/disable. But since idle function is >> per-cpu now, I think we still need idle_cpu_no_deep_c to check >> if we need to enter deep cstate on-the-fly. >> >> Thanks, >> -Aubrey >> >> > > Can the callback change the per-cpu idle function pointers? > > Bill
We need a kernel variable to disable Deep C-States on buggy hardware. Perhaps we can use idle_cpu_no_deep_c to always disable Deep C-States, and use a new cpudrv variable to enable/disable cstates in the idle loop? Bill
