From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA1CAC433EF for ; Fri, 4 Feb 2022 19:41:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234487AbiBDTlO (ORCPT ); Fri, 4 Feb 2022 14:41:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232901AbiBDTlJ (ORCPT ); Fri, 4 Feb 2022 14:41:09 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05F2AC061714 for ; Fri, 4 Feb 2022 11:41:09 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 61F8DCE22CB for ; Fri, 4 Feb 2022 19:41:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5274BC004E1; Fri, 4 Feb 2022 19:41:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644003665; bh=ckw2IXHCEaaDlGbJk3ekdL1tmOejjiEq11h34072JLU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YtIMQR3VihMcmi72JgNfzeKqWB74e72isUWpNNnCNS/0sj/lqTJi88aYoyAV+9TwO M1I4HYhYwQjImEfwDSYi6xQdecQEg2L3IjDm51YM2A80fOGMvGUwfBuNbIpwFCNsTI lKdYfeOav8SsCiOjexVf5QZRn7G6tlg5hxZS0J7Y5LTQddL7a+UTGfKD6Uh+XR+06k E8KEKIP8ni3C7bQeOeFO3L2nPtKpu+ywtNEhCe1f60tiKT+x/4n68i7fPQNjp0BKfr 01xj1UlQTQMgyAFo3snSt6TfIaKlR3eNGyS8Mw3EMwapHLHxBhQOILgL2mV7s77J3H MeK2gGxLssKVw== Date: Fri, 4 Feb 2022 19:41:01 +0000 From: Mark Brown To: Brian Norris Cc: Peng Fan , "rafael@kernel.org" , "linux-kernel@vger.kernel.org" , dl-linux-imx , "S.j. Wang" Subject: Re: regmap: mmio: lack of runtime_pm support for debugfs Message-ID: References: <1587620791-5279-1-git-send-email-peng.fan@nxp.com> <20200423104000.GD4808@sirena.org.uk> <20200423112244.GH4808@sirena.org.uk> <20200424103004.GB5850@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="+iMZOw02us7dat7E" Content-Disposition: inline In-Reply-To: X-Cookie: Torque is cheap. Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --+iMZOw02us7dat7E Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Feb 04, 2022 at 11:21:51AM -0800, Brian Norris wrote: > On Fri, Feb 4, 2022 at 11:02 AM Mark Brown wrote: > > Are you sure you wouldn't be better off with a cache here, or marking > > the registers as precious so they don't get read (perhaps conditionally > > to allow reading while the device is live)? > We do actually have a cache for the case I care about, but there's > also a debugfs file for bypassing that and...for some reason I'm > dealing with some diagnostic scripts that purposely toggle that. I'm > not sure how wise that is, but in general I like to reduce the number > of ways dumb user space can screw things up. I've even had to tell > people that recursively grepping through sysfs or debugfs is a bad > idea... Are you sure this extra thing that bypasses the cache isn't an out of tree patch? It really doesn't sound like a good idea to have that, and if people think they need it they probably have drivers doing something quite unfortunate. Or are you just looking at the upstream debugfs with some volatile registers? --+iMZOw02us7dat7E Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmH9gUwACgkQJNaLcl1U h9B6QQf/V8FpQD0c3GxBAmnKaiJB8IF+/cyPMz72rvNFzk4ZoFdsu2ByVfL+Zrj9 EZEOpisWGmEfzH/L8+pnBKYJu7JqoZWmTItTl2uTX1MBexqrXUko7XnKhYn0GeC1 ADBkssPDFNVGJIKZ8fB00Zx4vWkTUBtvgIxHGWfTPRlZyCsCv2Uq+4zefavk3WoJ swRa63Syj1MG0kAEU865WcMoCddNmmrEz4eQYv9zwRkOIY+JPB3bUzYrHcNV+USV jhRYn2Jdz4i+NHCASAGOB0PBvNrFlvDbA6r3mQPhG5r4gMpF6ki5PiQj6YyZ+mbj bm3bSj5cEpQra7AA79Kz8+XzE3NxUg== =cp59 -----END PGP SIGNATURE----- --+iMZOw02us7dat7E--