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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 52D96CD6E57 for ; Sun, 31 May 2026 22:01:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 99B9F112C48; Sun, 31 May 2026 22:01:07 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; secure) header.d=posteo.de header.i=@posteo.de header.b="JIFtCBuX"; dkim-atps=neutral Received: from mout02.posteo.de (mout02.posteo.de [185.67.36.66]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3C991112C48 for ; Sun, 31 May 2026 22:01:04 +0000 (UTC) Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 9C92A240105 for ; Mon, 1 Jun 2026 00:01:02 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1780264862; bh=cw7SuGmUUtz7Kl1motq+vhpCvWeJlxpaavxYphPtzDU=; h=Message-ID:Subject:From:To:Cc:Date:Autocrypt:Content-Type: MIME-Version:OpenPGP:From; b=JIFtCBuX19EGYI41p6DCXpH1ZolArWhHHF9Kd/efnYkiYJ+HP8BXsaSmY2kLhmRKs VYf1CX8uubEDUgwuAkmybZDw8uOeIIgYWtDbAXcbssp3y5KEvS1JbCQsw8ahSzvk2t +GTSbFaCLsJikQqYQ3/ytxU2jQmLNXHW1QxXJaBkvPkGCE00BP8OGa6Cr8NfxeKpro 8iGF8vRMOD3RNZpj/QbjcwEn/EcBE6pHnbIrfN4ctqd2pUdp3AfSNdwnroLDjFI5cj gHv/aPjRKgBaLZI39zIGk4HuQN9vPlClZHirblN8/+R9vzxTFr3if/RUnkh2B0ny+R 6ND7VbHZ04+MA== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4gT9yX2DYLz6v3p; Mon, 1 Jun 2026 00:00:52 +0200 (CEST) Message-ID: <7c30276759aaba8127275e602cb78783ec33bbe9.camel@posteo.de> Subject: Re: [PATCH v11 1/3] rust: add basic serial device bus abstractions From: Markus Probst To: Danilo Krummrich Cc: Markus Probst via B4 Relay , Rob Herring , Greg Kroah-Hartman , Jiri Slaby , Miguel Ojeda , Gary Guo , =?ISO-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Kari Argillander , "Rafael J. Wysocki" , Viresh Kumar , Boqun Feng , David Airlie , Simona Vetter , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-pm@vger.kernel.org, driver-core@lists.linux.dev, dri-devel@lists.freedesktop.org Date: Sun, 31 May 2026 22:00:54 +0000 In-Reply-To: References: <20260531-rust_serdev-v11-0-dee8e0d830f1@posteo.de> <20260531-rust_serdev-v11-1-dee8e0d830f1@posteo.de> <12fa6237168ecf6dc65ebf46118beeb5c51f3d1c.camel@posteo.de> Autocrypt: addr=markus.probst@posteo.de; prefer-encrypt=mutual; keydata=mQINBGiDvXgBEADAXUceKafpl46S35UmDh2wRvvx+UfZbcTjeQOlSwKP7YVJ4JOZrVs93 qReNLkOWguIqPBxR9blQ4nyYrqSCV+MMw/3ifyXIm6Pw2YRUDg+WTEOjTixRCoWDgUj1nOsvJ9tVA m76Ww+/pAnepVRafMID0rqEfD9oGv1YrfpeFJhyE2zUw3SyyNLIKWD6QeLRhKQRbSnsXhGLFBXCqt 9k5JARhgQof9zvztcCVlT5KVvuyfC4H+HzeGmu9201BVyihJwKdcKPq+n/aY5FUVxNTgtI9f8wIbm fAjaoT1pjXSp+dszakA98fhONM98pOq723o/1ZGMZukyXFfsDGtA3BB79HoopHKujLGWAGskzClwT jRQxBqxh/U/lL1pc+0xPWikTNCmtziCOvv0KA0arDOMQlyFvImzX6oGVgE4ksKQYbMZ3Ikw6L1Rv1 J+FvN0aNwOKgL2ztBRYscUGcQvA0Zo1fGCAn/BLEJvQYShWKeKqjyncVGoXFsz2AcuFKe1pwETSsN 6OZncjy32e4ktgs07cWBfx0v62b8md36jau+B6RVnnodaA8++oXl3FRwiEW8XfXWIjy4umIv93tb8 8ekYsfOfWkTSewZYXGoqe4RtK80ulMHb/dh2FZQIFyRdN4HOmB4FYO5sEYFr9YjHLmDkrUgNodJCX CeMe4BO4iaxUQARAQABtCdNYXJrdXMgUHJvYnN0IDxtYXJrdXMucHJvYnN0QHBvc3Rlby5kZT6JAl QEEwEIAD4CGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AWIQSCdBjE9KxY53IwxHM0dh/4561 D0gUCaIZ9HQIZAQAKCRA0dh/4561D0pKmD/92zsCfbD+SrvBpNWtbit7J9wFBNr9qSFFm2n/65qen NNWKDrCzDsjRbALMHSO8nigMWzjofbVjj8Nf7SDcdapRjrMCnidS0DuW3pZBo6W0sZqV/fLx+AzgQ 7PAr6jtBbUoKW/GCGHLLtb6Hv+zjL17KGVO0DdQeoHEXMa48mJh8rS7VlUzVtpbxsWbb1wRZJTD88 ALDOLTWGqMbCTFDKFfGcqBLdUT13vx706Q29wrDiogmQhLGYKc6fQzpHhCLNhHTl8ZVLuKVY3wTT+ f9TzW1BDzFTAe3ZXsKhrzF+ud7vr6ff9p1Zl+Nujz94EDYHi/5Yrtp//+N/ZjDGDmqZOEA86/Gybu 6XE/v4S85ls0cAe37WTqsMCJjVRMP52r7Y1AuOONJDe3sIsDge++XFhwfGPbZwBnwd4gEVcdrKhnO ntuP9TvBMFWeTvtLqlWJUt7n8f/ELCcGoO5acai1iZ59GC81GLl2izObOLNjyv3G6hia/w50Mw9MU dAdZQ2MxM6k+x4L5XeysdcR/2AydVLtu2LGFOrKyEe0M9XmlE6OvziWXvVVwomvTN3LaNUmaINhr7 pHTFwDiZCSWKnwnvD2+jA1trKq1xKUQY1uGW9XgSj98pKyixHWoeEpydr+alSTB43c3m0351/9rYT TTi4KSk73wtapPKtaoIR3rOFHLQXbWFya3VzLnByb2JzdEBwb3N0ZW8uZGWJAlEEEwEIADsWIQSCd BjE9KxY53IwxHM0dh/4561D0gUCaIO9eAIbAwULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgAAKCR A0dh/4561D0oHZEACEmk5Ng9+OXoVxJJ+c9slBI2lYxyBO84qkWjoJ/0GpwoHk1IpyL+i+kF1Bb7y Hx9Tiz8ENYX7xIPTZzS8hXs1ksuo76FQUyD6onA/69xZIrYZ0NSA5HUo62qzzMSZL7od5e12R6OPR lR0PIuc4ecOGCEq3BLRPfZSYrL54tiase8HubXsvb6EBQ8jPI8ZUlr96ZqFEwrQZF/3ihyV6LILLk geExgwlTzo5Wv3piOXPTITBuzuFhBJqEnT25q2j8OumGQ+ri8oVeAzx24g1kc11pwpR0sowfa5MvZ WrrBcaIL7uJfR/ig7FyGnTQ1nS3btf3p0v8A3fc4eUu/K2No3l2huJp3+LHhCmpmeykOhSB63Mj3s 3Q87LD0HE0HBkTEMwp+sD97ZRpO67H5shzJRanUaDTb/mREfzpJmRT1uuec0X2zItL7a6itgMJvYI KG29aJLX3fTzzVzFGPgzVZYEdhu4y53p0qEGrrC1JtKR6DRPE1hb/OdWOkjmJ75+PPLD9U5IuRd6y sHJWsEBR1F0wkMPkEofWsvMYJzWXx/rvTWO8N4D6HigTgBXAXNgbc3IHpHlkvKoBJptv6DRVRtIrz 0G0cfBY0Sm7he4N2IYDWWdGnPBZ3rlLSdj5EiBU2YWgIgtLrb8ZNJ3ZlhYluGnBJDGRqy2jC9s1jY 66sLA9rQZMHhJTzMyIDwweGlvMzJAcG9zdGVvLmV1PokCbQQTAQgAVxYhBIJ0GMT0rFjncjDEczR2 H/jnrUPSBQJpa71VGxSAAAAAAAQADm1hbnUyLDIuNSsxLjExLDIsMgIbAwULCQgHAgIiAgYVCgkIC wIEFgIDAQIeBwIXgAAKCRA0dh/4561D0gKJD/9uOQKYlsDoQX65Gd0LiMT0C+5vXgr3VI0PHDOwcv 51fJ3A1vNyPZRFPGrz8+mDEXUQOF/INfnz5Tu1QHwf+iYcWcTGAN/FHgVR6ET6VBNU2hJaKhu+Ggo kjYyJTOvyX+3yNRUfSny0GjTjIPuPTErjqmHF+BtjXslpgwqnNMznf3lRIuUjRORupos6p3k1DndE 5vzUTmXSvMyXyOD2KhBl/kL76k0bHYyAQytZPag12pltrtFbA/r2phDGN2si8PooDT99bSTJjaM45 MTAAHbHKJfvgfK41bNFD5mMtpWpL195XRtS0Nrxdg3PaYBxN5gtTG0RyZfpYRlkdEhm+jj/8RxuSG i/qdhRdbiI7K2IELWeQVHSNDi9JabR/UzlR4NSnhfAjRIVlRM+eFbUl8XwxwVrAkojF5IraH2qRvg VCmuFsHUW07FUlrDrzpjXsD73cKppoFGDCdDR0BHJepXbFLS9+AqkT+guRJlnCTg2p+TQtnbwPgKp Vj98JixovCl99zRYTsL2bRNU5+q8iET65VMJ1ydyNanvLd5vI/NqDkXhlXLsGmdaDTtu4R21PkToX dQNGrZ91M9nlIBKw8Y7c7xZ4098qX2b8JX/CxD+gC1r4C8vuA3GkhFLx+KlkON7LyiJPkrePp6Qky jfGillcaQOqFZ3WwVqyzG1BUfTow== Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-uBVcWHTLCDJlFvAW7yIN" MIME-Version: 1.0 OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" --=-uBVcWHTLCDJlFvAW7yIN Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sun, 2026-05-31 at 23:49 +0200, Danilo Krummrich wrote: > On Sun May 31, 2026 at 9:42 PM CEST, Markus Probst wrote: > > I just noticed, is it even possible to use SRCU here? Currently the mut= ex not > > only ensures that no drvdata access happens after drvdata drop, but als= o that > > the receive_buf waits for the probe to complete, as the drvdata hasn't = been > > initialized yet. >=20 > Yeah, if you drop the completion, you need the mutex. Is the performance impact on an mutex or on srcu + completion higher? >=20 > (In case it wasn't discussed in previous versions already, there is also = the > option to just attach separate private data to the receive callback, whic= h would > avoid this synchonization problem in the first place. >=20 > You could have serdev::Device::open(), which takes its own private = data > and a corresponding close(), this way you'd allow drivers to control whet= her > they want the serial line "open" or not. You just need to make sure it is= closed > eventually.) This would add complexity with types, as we need to ensure that write, set_baudrate, set_parity etc. does not run when closed. >=20 > That said, I don't know what turns out to be the better approach. And may= be it > simply isn't something this initial series has to tackle? I think your dr= iver > does not implement the receive callback? The initial driver with only leds: no. That changes once the driver also takes care of hwmon (ADC sensor and fan failure) and input (power button and possibly other buttons). Thanks - Markus Probst --=-uBVcWHTLCDJlFvAW7yIN Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQJPBAABCAA5FiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IFAmocr4wbFIAAAAAABAAO bWFudTIsMi41KzEuMTIsMiwyAAoJEDR2H/jnrUPSDloP/i5cj/y4hJYdAj3PLaRA SO2PB7uyThh7YoEfyWXRIR/2qrAF1eZwc/1nHpEnwvFBH2VB3lF4imS/YIWkQRg9 86hBFLnuQhYWKzN25Pt8PHNduUT6oysTeGmu8gW7E6pOEvFeP7r51y5l/D4fE0tX ieEnqWfOVAqKHmngIEwCBWvzNTuZwjFVmhysLS7QtnYdfqtjVOseE8560qnpq5nU jJhjlNK9SAEvkrEulEV016PfFhyvy7LxvfOTF1K39/gc0jwPB7fVTPyNkVa0UYJH bHqQaT7w+nixNiuW90IzkuAeN8djGroE7F6jwFG25xHqaXhpb7ll2t4cZHvePNA1 XaotnSTCIc4Jwrtfxz5UVzuBheEQcZoop2pFRQTD0saOEIxJzaBy3aSXZ9fpc2RZ hkzkqeSoUxiR81n3iZ0iUnZBF/XxOOaj6uoVxt/4V9xCeBV6qa36KXhVjiyajQRM Ro11UsVVJ5X3QgihOIWozryynhJWwPTkEwSEy/SXfWABGI958fwlXql/OLfn5ANM Fn8opkwAXNlmrukYXcVi2RJtU7zcVpcVsCbq1koweJm3KWIUSY4+XNaHUkxPVAmW E8k+aINXLowfEw6Q3uJFvwZGLJIi3BZMXwk6wYiLNOzZgOYlIvJfPT/Y3PetNOUE 5XkrbC/VmOIPOTxhILwLlB3+ =Q0na -----END PGP SIGNATURE----- --=-uBVcWHTLCDJlFvAW7yIN--