From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ducrot Bruno Subject: Re: [PATCH][DOCUMENTATION BUGFIX] latency in micro-, not nanoseconds Date: Mon, 10 Nov 2003 18:15:33 +0100 Sender: cpufreq-bounces@www.linux.org.uk Message-ID: <20031110171533.GS21970@poupinou.org> References: <20031104160816.GA9187@brodo.de> <20031110163209.GP10144@redhat.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20031110163209.GP10144@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: cpufreq-bounces@www.linux.org.uk Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dave Jones Cc: cpufreq@www.linux.org.uk, Dominik Brodowski On Mon, Nov 10, 2003 at 04:32:09PM +0000, Dave Jones wrote: > On Tue, Nov 04, 2003 at 05:08:16PM +0100, Dominik Brodowski wrote: > > All drivers [davej, can you please verify for powernow-k7?] set the > > transition_latency time in microseconds, even though the core demanded > > nanoseconds. Instead of fixing up the drivers, fix up the core... > > Hmm, I think you've unearthed a bug. > > The 'latency' we read from the BIOS is in microseconds, but the hardware > wants it in units of 10ns. We do the necessary maths, and everything is fine. > But we're also storing that result in .. > > policy->cpuinfo.transition_latency = latency; > > Which is possibly not the right thing to be doing. > I think we want to be storing the 'pre 10ns munging' value here correct? > Well, maybe we have to double it as well (there is actually 2 steps, the VID change and the FID change, each having 'latency' 1e(-8) second)... something like: policy->cpuinfo.transition_latency = latency / 50; perhaps? -- Ducrot Bruno -- Which is worse: ignorance or apathy? -- Don't know. Don't care.