From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Jarzmik Subject: Re: [PATCH v2 1/3] net: irda: pxaficp_ir: use sched_clock() for time management Date: Tue, 22 Sep 2015 21:27:51 +0200 Message-ID: <87r3lqp83s.fsf@belgarion.home> References: <87eghyso6u.fsf@belgarion.home> <20150917.145106.1238429841434804906.davem@davemloft.net> <87si6br8ev.fsf@belgarion.home> <20150921.161235.605756522215336833.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain Cc: samuel@sortiz.org, petr.cvek@tul.cz, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, arnd@arndb.de To: David Miller Return-path: In-Reply-To: <20150921.161235.605756522215336833.davem@davemloft.net> (David Miller's message of "Mon, 21 Sep 2015 16:12:35 -0700 (PDT)") Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org David Miller writes: > From: Robert Jarzmik > Date: Fri, 18 Sep 2015 18:36:56 +0200 > >> Which brings me to wonder which is the more correct : >> (a) replace to reproduce the same calculation >> Previously mtt was compared to a difference of 76ns steps (as 307ns / 4 = >> 76ns): >> while ((sched_clock() - si->last_clk) * 76 < mtt) >> >> (b) change the calculation assuming mtt is in microseconds : >> while ((sched_clock() - si->last_clk) * 1000 < mtt) >> >> I have no IRDA protocol knowledge so unless someone points me to the correct >> calculation I'll try my luck with (b). > > "a" would be "safer" and less likely to break anything, although as > you say "b" might be more correct. Indeed. Well, let me try (b) then. I'll add in the commit message the timings change, and if anybody complains a regression pops out, I'll provide a patch to fallback to (a). Cheers. -- Robert