From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nishanth Menon Subject: Re: [PATCH] cpufreq: Stop BUGing the system Date: Wed, 24 Dec 2014 09:06:05 -0600 Message-ID: <549AD65D.4010000@ti.com> References: <1418831495-26958-1-git-send-email-nm@ti.com> <20141218144915.GA29004@kahuna> <3146996.LXve8MJFme@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:46869 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751867AbaLXPGK (ORCPT ); Wed, 24 Dec 2014 10:06:10 -0500 In-Reply-To: <3146996.LXve8MJFme@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" , Viresh Kumar Cc: Kevin Hilman , Linux Kernel Mailing List , "linux-pm@vger.kernel.org" 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 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. -- Regards, Nishanth Menon