On 8/1/06, Tim Bird <tim.bird at am.sony.com> wrote: > david singleton wrote: > > On Aug 1, 2006, at 3:09 AM, Matthew Locke wrote: > >>Well, no one is suggesting a user define and install that info. > >>Operating point creation will be done by someone who understands the > >>system (system designer) regardless of the method used to get the > >>operating points in the kernel. > > > > It sounds to me like they don't want to have to change kernel code and > > recompile the kernel > > to get a new operating point. > > > > It sounds like they are talking about a dynamic operating point as a > > loadable > > module, which would fit perfectly with the PowerOp scheme, since it's > > the > > system designer who would be creating the new dynamic operating point, > > not the user. > > Often, in the embedded world, the person defining the operating > states will not be a kernel developer, and may not be comfortable > with, or capable of, creating a kernel module. (There are > significant sections of the embedded space where modules are > not used at all, and no module support is compiled into the > kernel.) In these cases, requiring loadable module support > for runtime OPs would be a problem. In my understanding, runtime OPs should be registered via configfs. Modules with definitions are worse yet acceptable. > > The point of PowerOp is that the system designer creates (and validates) > > the operating points that the hardware vendor supports, not the user. > > > > A system designer creating a new operating point as a loadable > > module would satisfy this requirement, and the user would not > > be able to put the system into an undefined state, either by accident > > or maliciously. > > > > OK, I think I understand better your objection to user-space > created operating points. In embedded projects, it is often > assumed that no one but the system designer has access to > arbitrary user space programs. Hence, it sometimes doesn't > register that an end user could or would utilize a particular > interface, just because it existed. Well, why Unix allows root to do 'rm -rf'? It can put the system in an undefined state... :P Speaking seriously, if restrictions are comprehensive, then only correct OPs will be created run-time or whenever. And being able to create OPs runtime is a very important requirement for PowerOP, for many reasons.
