On Fri, Nov 12, 2021 at 01:37:27PM +0200, Andy Shevchenko wrote: > On Fri, Nov 12, 2021 at 12:46:56PM +0200, Laurent Pinchart wrote: > > On Fri, Nov 12, 2021 at 10:32:31AM +0000, Dave Stevenson wrote: > > > On Thu, 11 Nov 2021 at 22:04, Laurent Pinchart wrote: > > > > Sorry, just my two-penneth as someone who has to support general > > > users, rather than just develop platforms or address specific use > > > cases. > > > > As mentioned above, I certainly don't oppose improving power management > > for VCMs, as well as the VCM control API in general, as long as we can > > cover all use cases. I'm not familiar enough with the use cases to tell > > whether making the kernel side more "clever" would be just fine or could > > cause issues. > > Personally I found the > > kernel <--> library in userspace <--> another library or app > > schema is more flexible in many ways: > - we unburden kernel from the heavy code that has nothing to > do directly with HW > - we allow nevertheless to use kernel ABIs if needed > - we decrease burden of the ABI evolution by doing it in only > two places I think that's generally true (provided the low-level userspace library is well designed). In this specific case, we're moving towards that model, and even if it ends up being better, I agree with Dave that the transition can be painful. > After all this kind of schema might lead us at some point to the > shifting of 'we don't break user space' paradigm to the 'we hardly > try not to break user space and do not break library ABIs / APIs > in user space'. Is that an officially allowed policy for kernel subsystems ? -- Regards, Laurent Pinchart
