From mboxrd@z Thu Jan 1 00:00:00 1970 From: public_timo.s@silentcreek.de (Timo Sigurdsson) Date: Tue, 4 Aug 2015 10:51:30 +0200 (CEST) Subject: [linux-sunxi] [PATCH] ARM: dts: sunxi: Raise minimum CPU voltage for sun7i-a20 to a level all boards can supply In-Reply-To: <20150803093420.GC2564@lukather> References: <1438543386-7253-1-git-send-email-public_timo.s@silentcreek.de> <20150803090352.621CC6C80865@dd34104.kasserver.com><20150803093420.GC2564@lukather> Message-ID: <20150804085130.602FA6C83EF9@dd34104.kasserver.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Maxime, Maxime Ripard schrieb am 03.08.2015 11:34: > On Mon, Aug 03, 2015 at 11:03:52AM +0200, Timo Sigurdsson wrote: >> Julian Calaby schrieb am 03.08.2015 06:22: >> > My only real objection here is are there boards that can go down to >> > 0.9v and if so, won't this change make them less power efficient in >> > the almost-idle case? And are those power savings enough to justify >> > not accepting this patch? >> >> It will probably make those boards less power efficient, yes. On the >> other hand, boards that have their CPU regulator set to min. 1.0V might >> also draw more power because the lowest frequency is not available, >> even though the savings due to frequency are likely to be lower than >> the savings due to voltage. > > Guys, isn't this whole discussion a bit moot? We're not doing any kind > of power management but cpufreq, so maybe there's a lot more to do > before we actually can have these kind of arguments? > > Plus this OPP has never been used anyway, so this patch is not going > to increase the power consumption either. You are right. When I wrote that, I was under the impression that the Olinuxino Lime 2 board at least used this setting since it has has a cpu regulator defined to go as low as 0.7V. But now I checked again and see the regulator is not referenced in the cpu node, so I guess cpufreq doesn't use it. So, this discussion was really hypothetical and more importantly, as you mentioned, it's an out-of-spec opp that shouldn't be supported anyway. Thanks, Timo