Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754155AbaFUTez (ORCPT ); Sat, 21 Jun 2014 15:34:55 -0400 Received: from mail-oa0-f43.google.com ([209.85.219.43]:39713 "EHLO mail-oa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751954AbaFUTey (ORCPT ); Sat, 21 Jun 2014 15:34:54 -0400 MIME-Version: 1.0 In-Reply-To: <20140621185051.GA25094@amd.pavel.ucw.cz> References: <20140621180201.GA4621@amd.pavel.ucw.cz> <20140621185051.GA25094@amd.pavel.ucw.cz> Date: Sat, 21 Jun 2014 15:34:54 -0400 X-Google-Sender-Auth: DdfwduFdDQnyloGfm_gti8l5mpo Message-ID: Subject: Re: unparseable, undocumented /sys/class/drm/.../pstate From: Ilia Mirkin To: Pavel Machek Cc: kernel list , Ben Skeggs , Greg KH , Alexandre Courbot , David Airlie , "dri-devel@lists.freedesktop.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 21, 2014 at 2:50 PM, Pavel Machek wrote: > On Sat 2014-06-21 14:22:59, Ilia Mirkin wrote: >> On Sat, Jun 21, 2014 at 2:02 PM, Pavel Machek wrote: >> > Hi! >> > >> > AFAICT, pstate file will contain something like >> > >> > 07: core 100 MHz memory 123 MHz * >> > 08: core 100-200 MHz memory 123 MHz >> > >> > ...which does not look exactly like one-value-per-file, and I'm pretty >> > sure userspace will get it wrong if it tries to parse it. Plus, I >> > don't see required documentation in Documentation/ABI. > ... >> >> FTR, this file has been in place since 3.13, and there was a different >> file before it (performance_levels), with a comparable format since >> much earlier (definitely 3.8, probably earlier). I think it's meant >> a > > According to the article, it is only starting to work now. I know > articles can be wrong, but I don't have that hardware... Sorry if it > is the case. Commit 26fdd78cce3f51a49e1f2d3ad27ee893a28d220e introduced this particular one. Commit 330c5988ee78045e6a731c3693251aaa5b0d14e3 had introduced the former version, which was removed in 3.13, replaced with the new one. > >> lot more for people looking at it and echo'ing stuff to it to modify >> the levels (where supported), than for programs parsing it. Perhaps >> sysfs is the wrong place for this -- what is the right place? debugfs? > > debugfs would work, yes. > Pavel > -- > (english) http://www.livejournal.com/~pavelmachek > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/