Paul Walmsley <paul@xxxxxxxxx> writes: > Hi, > > On Tue, 17 Nov 2009, Kevin Hilman wrote: > >> When checking measured [de]activate latencies against expected >> latencies, only print warning if driver has provided a non-zero >> latency. >> >> This allows drivers to set their [de]activate latencies to zero when >> they are not known, or are don't care, and the omap_device core will >> not complain about unexpected latencies. > > I'm concerned that this will effectively mean that no driver maintainers > will bother to measure these latencies. > > These are necessary for a reasonable implementation of > omap_pm_set_max_dev_wakeup_lat(). They should not be difficult to > measure: boot at the lowest-performance OPPs with the latencies > uninitialized; then these warnings should indicate numbers that can > be plugged back into the omap_device structure. But perhaps I am > misunderstanding the point you are making? Part of the issue is being able to do a quick conversion, without needing to measure latencies (which I'm guilty of.) The other part was that I was thinking (the RFC part) was that it might be useful for performance reasons to not do do any measuring at all. Of course, this would preclude a useful max_dev_wakeup_lat() but we could warn about that. But, for now I agree. I think getting these latencies in place is more important than having an optimization for avoiding measurement for now. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
