From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756622AbaGWNvg (ORCPT ); Wed, 23 Jul 2014 09:51:36 -0400 Received: from mail-pd0-f174.google.com ([209.85.192.174]:64618 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751549AbaGWNvd (ORCPT ); Wed, 23 Jul 2014 09:51:33 -0400 Date: Wed, 23 Jul 2014 15:51:28 +0200 From: Thierry Reding To: Viresh Kumar Cc: Tuomas Tynkkynen , "linux-tegra@vger.kernel.org" , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" , "linux-pm@vger.kernel.org" , Stephen Warren , Peter De Schrijver , Prashant Gaikwad , Mike Turquette , "Rafael J. Wysocki" , Paul Walmsley , "devicetree@vger.kernel.org" Subject: Re: [PATCH v2 14/16] cpufreq: Add cpufreq driver for Tegra124 Message-ID: <20140723135127.GB14263@ulmo.nvidia.com> References: <1405957142-19416-1-git-send-email-ttynkkynen@nvidia.com> <1405957142-19416-15-git-send-email-ttynkkynen@nvidia.com> <20140723065412.GA15759@ulmo.nvidia.com> <20140723072442.GC15759@ulmo.nvidia.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="CdrF4e02JqNVZeln" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --CdrF4e02JqNVZeln Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jul 23, 2014 at 01:55:57PM +0530, Viresh Kumar wrote: > On 23 July 2014 12:54, Thierry Reding wrote: > > ARM_TEGRA_CPUFREQ is still optional, so the select only applies when the > > Tegra cpufreq driver is enabled. This is mostly just out of convenience, > > though. The Tegra cpufreq driver uses the generic CPU0 cpufreq driver so > > a select will automatically pull in the necessary dependency. With a >=20 > Not necessarily. cpufreq-cpu0 can have few unmet dependency. And so > there are chances that tegra driver is compiled but cpufreq-cpu0 isn't as > we didn't mention it as a *hard* dependency. >=20 > And so at boot, there wouldn't be any cpufreq support even when tegra's > cpufreq driver is available. >=20 > Though, menuconfig may give some warnings no such situations. >=20 > > "depends on" the Tegra cpufreq driver only becomes available after > > you've selected GENERIC_CPUFREQ_CPU0, which is somewhat unintuitive. > > > > To illustrate with an example: as a user, I want to enable CPU frequency > > scaling on Tegra. So I use menuconfig to navigate to the "CPU Frequency > > scaling" menu (enable it if not available yet) and look for an entry > > that says "Tegra". But I can't find it because it's hidden due to the > > lack of GENERIC_CPUFREQ_CPU0. That the Tegra CPU frequency driver uses a > > generic driver is an implementation detail that users shouldn't have to > > be aware of. >=20 > Don't know, the guy compiling out stuff should be knowledgeable enough to > have a look why tegra cpufreq entry isn't shown in menu. As, probably the > above problem I mentioned looks to be of more significance than this one, > atleast to me :) >=20 > And, another thing to mention is that CONFIG_TEGRA_CPUFREQ is valid > for earlier platforms as well and so a select/depends wouldn't be valid f= or > earlier platforms. We probably need another Kconfig entry here. Yes, sounds like a new Kconfig entry for this specific driver would be a better approach and should remove all the above concerns. Thierry --CdrF4e02JqNVZeln Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIbBAEBAgAGBQJTz73eAAoJEN0jrNd/PrOhLJYP+IuuRTEEvQoTQ1Y2AMHVsLTf tPei0ThoS2Mav5HMWIGOKB8kbmqf0koRR4Z+SHRlwrdyU7VN9aNmDXUY2MCZWs9X XLmzPaQAFcvciI+8t6GT0uJBBRCzhC06+PQdKeMEaTyqKhsDaC0fmbQQYiaRzMBe F2YG18PY3jDeEXid+OYIuwOt9bH3EGp1Of+9BbFANmBQyG8Jdt6Un7cAWYJj/dTi vl4eekndo+Hd0n3QYmW/6Urzb4DEyY+giiZ6d7MLDZs/zx7s+zoCzxgKo4JbMizy LlhKyE1FHV8gM7uwfVxyM3f1fv0LGmXYpfv8KfU9+XHK0IDQKjpfAZ7A+TA5bZ1+ o3U+0nno7E0TSWIJcjuStUP1M8QVlVum87D01zatkgsn/hm/6XxijH+8Br6k1R3E cIDQS7+ziEYSpjTrvV4t9pOHmxe1HlhC5yfBs8m1r+gAQBdAKuZeTiDO1DAbf3Ka ok9QlOCDWSwCAYMdGrv/qyrkA4/U6aqZtb1xvW5uucc081TnN4cQcW/1KcWhinrQ EBVxGAVEaGZnbhlml8SqqVQEzNFsT+aDzkCQYu8fU7g2xEJedgJNv3TpLqxewYFW GY2iJcj+QdgqaOoTpWBbGJvNjiqb8iFR0xK+odB/+ops16B19o0rnUffmujdtyJC TlT/ri2zehYTNtTnkRg= =zC7T -----END PGP SIGNATURE----- --CdrF4e02JqNVZeln--