On Wednesday, December 24, 2014 09:06:05 AM Nishanth Menon wrote: > On 12/18/2014 08:08 PM, Rafael J. Wysocki wrote: > > On Friday, December 19, 2014 07:11:19 AM Viresh Kumar wrote: > >> On 18 December 2014 at 20:19, Nishanth Menon <[email protected]> wrote: > >>> I can add "could be unstable" -> the point being there can be psuedo > >>> errors reported in the system - example - clock framework bugs. Dont > >>> just stop the boot. example: what if cpufreq was a driver module - it > >>> would not have rescued the system because cpufreq had'nt detected the > >>> logic - if we are going to force this on the system, we should probably > >>> not do this in cpufreq code, instead should be somewhere generic. > >>> > >>> While I do empathise (and had infact advocated in the past) of not > >>> favouring system attempting to continue at an invalid configuration and > >>> our attempt to rescue has failed - given that we cannot provide a > >>> consistent behavior (it is not a core system behavior) and potential of > >>> a false-postive (example clk framework or underlying bug), it should be > >>> good enough to "enhance" WARN to be "severe sounding enough" to > >>> flag it for developer and continue while keeping the system alive as > >>> much as possible. > >> > >> There is no way out for the kernel to know if its a false positive or a > >> real > >> bug. And in the worst case, it can screw up a platform completely. > >> > >> I am still not sure if changing it to a WARN would be good idea. > >> > >> @Rafael: Thoughts ? > > > > I'm a bit divided here. On the one hand I don't like BUG_ON() as a rule > > and it > > is used in too many places where it doesn't have to be used. > > > > On the other hand, in this particular case, I'm not sure if allowing the > > system > > to run without cpufreq when it might rely on it for CPU cooling, for one > > example, > > is a good idea. > > but then, CPUFReq is not a mandatory feature - we could as well do the > same with CPU_FREQ disabled.
Some platforms pretty much require CPU_FREQ and will always have it set, but with the $subject patch they may end up not using it. So this isn't a valid argument to me, sorry. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
