From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH] ARM: dts: sunxi: Raise minimum CPU voltage for sun7i-a20 to a level all boards can supply Date: Mon, 3 Aug 2015 11:28:39 +0200 Message-ID: <20150803092839.GB2564@lukather> References: <1438543386-7253-1-git-send-email-public_timo.s@silentcreek.de> Reply-To: maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="RvfD4wEUHtVM+5Ki" Return-path: Content-Disposition: inline In-Reply-To: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Julian Calaby Cc: Chen-Yu Tsai , public_timo.s-fWgRPtSzPNU3WX+qO2AYSQ@public.gmane.org, Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Russell King , devicetree , "Mailing List, Arm" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-sunxi List-Id: devicetree@vger.kernel.org --RvfD4wEUHtVM+5Ki Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline On Mon, Aug 03, 2015 at 02:22:13PM +1000, Julian Calaby wrote: > >> Is the code that uses this smart enough to sensibly switch between two > >> operating points with the same frequency and different voltages? If > >> so, maybe just add a 144MHz @ 1.0v operating point? > > > > You could try. Though I really don't see much to gain here. > > From what I recall, lower frequency = less power usage, though my > experience is from x86 laptops, not ARM SoCs and I'm sure I'm missing > a lot of details. This is the sort of thing that requires thorough > testing on a dev board. Not on *a* dev board. On virtually all the A20 SoCs ever produced. If you have a setting that works better for *your* SoC, fine, patch your DT, but that's not going to be a default if it's outside of the SoC operating range. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --RvfD4wEUHtVM+5Ki--