From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: Re: [PATCH 1/4] intel_idle: stop using driver_data for static flags Date: Sat, 02 Feb 2013 15:18:22 -0500 Message-ID: <510D748E.4010605@kernel.org> References: <1359691896-23567-1-git-send-email-lenb@kernel.org> <9a38405338d7464c852c4524465f84f8a2ac22fb.1359691799.git.len.brown@intel.com> <510B8059.5040609@linaro.org> <510C0C22.4000801@kernel.org> <510C3EC5.3060709@linaro.org> <510C7708.4080707@kernel.org> <510CDFF1.80408@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ve0-f170.google.com ([209.85.128.170]:61711 "EHLO mail-ve0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758076Ab3BBUSZ (ORCPT ); Sat, 2 Feb 2013 15:18:25 -0500 In-Reply-To: <510CDFF1.80408@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Daniel Lezcano Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Lists Linaro-dev >> I think that a driver's private flag definitions >> should remain local to the driver. It makes no sense >> to pollute the name space of other drivers for stuff >> that doesn't mean anything to them. MWAIT is pretty >> specific to x86 -- and re-naming it to something 'generic' >> isn't going to make the code easier to read. > > Ok, let me rephrase it because I think how it was presented was not clear. > > As we want to use the half of the state flags for private purpose, I > suggested to add the encoding/decoding function in the shared header file. > > The mwait eax flags are not encoded and the CPUIDLE_FLAG_TLB_FLUSHED is > encoded. > > I suggested to unify both and to use an encoding function from the > shared header file. > > #define CPUIDLE_PRIVATE_FLAGS(_flags_) \ > ((_flags_) << 16) & CPUIDLE_DRIVER_FLAGS_MASK > > For example: > > #define FLAG_TLB_FLUSHED CPUIDLE_PRIVATE_FLAGS(0x1) > #define FLAG_MWAIT_C1 CPUIDLE_PRIVATE_FLAGS(0x0) > #define FLAG_MWAIT_C2 CPUIDLE_PRIVATE_FLAGS(0x10) > #define FLAG_MWAIT_C3 CPUIDLE_PRIVATE_FLAGS(0x20) > #define FLAG_MWAIT_C4 CPUIDLE_PRIVATE_FLAGS(0x30) > #define FLAG_MWAIT_C5 CPUIDLE_PRIVATE_FLAGS(0x40) > #define FLAG_MWAIT_C6 CPUIDLE_PRIVATE_FLAGS(0x52) > > And then: > > ... > > .flags = FLAG_TLB_FLUSHED | FLAG_MWAIT_C2 | CPUIDLE_FLAG_TIME_VALID I like your syntax better than what I used -- thanks for suggesting it. I can't use it as-is, however, because I really do need to be able to support unique parameters on each entry (eg. different flags for C3 on different processors). When some of the logical and functional changes in flux settle out I'll come back to re-visit the syntax. thanks, -Len Brown, Intel Open Source Technology Center