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 F35EDC07545 for ; Tue, 24 Oct 2023 13:12:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4958310E3B6; Tue, 24 Oct 2023 13:12:44 +0000 (UTC) Received: from mail-lf1-x142.google.com (mail-lf1-x142.google.com [IPv6:2a00:1450:4864:20::142]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3FCDE10E3B6; Tue, 24 Oct 2023 13:12:43 +0000 (UTC) Received: by mail-lf1-x142.google.com with SMTP id 2adb3069b0e04-507b9408c61so6111493e87.0; Tue, 24 Oct 2023 06:12:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1698153161; x=1698757961; darn=lists.freedesktop.org; h=mime-version:references:in-reply-to:message-id:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to; bh=TENfBjhU132BqHx7e5lh2Xj82u8/6PsMbhLSeVzUVmE=; b=V/tvOW9RK6WM+DD+xwDfDYNXEy6xP07EJ7NGzxWGQsrl3mg7K5fQrSzBg+dq7zUVzE flrmtVh5xCvAUlleZdzlhlclZyK/zMN32NRVQo9xw5BiVsYAvYK4B05YmGESTUzRp9M4 beLWeEQREbAyJB3Y5T3xJRdJgpW0Z0yKHW25CjpFmmzwmHnVWv4jcJWKcS2usW2Dj7fk efhylfiB9e9grtV/hVqENZY3eHi/e5GS5ixSX4aetwh4sCxkAounrqm+c5Y4OLr6KVrL ZpVM+rgbfJQ5JQAJ6QHpxwU1+mB9NOmV6XF8whlA4m5NtZXwNUNb0BV4IkJfJ+Y5d2iJ rYRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698153161; x=1698757961; h=mime-version:references:in-reply-to:message-id:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=TENfBjhU132BqHx7e5lh2Xj82u8/6PsMbhLSeVzUVmE=; b=fWg/t6ZJ2Lyjjg0gb6iBR6UNZNgbS+k4QCodykByKTShgwC/tVu5mhxRDaZi/M/9xc wX+HhaUDX6RVVMuLmg+yezT/C1kbRdZOjk3Zqy+r1ocu9uERDk3aU0QYFTKtvT7ogYj5 PxcHtSCMXfAcH01PZnat0j89WQh8DZeZPCIjXccnT9lXamNk1d/DuQoi0TcdjbmJFD/B ACBIYBu7radypQ9QENhjKZfWPg99D+xyZg/y/y+y0Sgy0fEsRKcIvwRUrbBJpeZoZexh nUHQcPgsxN5EfijP0EYom5gM/nLt+bPeNOyF8/y7LS4Onu+j1Tz8uxyBjhHGZ1P99rmf AAvg== X-Gm-Message-State: AOJu0YxQAomgjRn2CD9bHNPjLPvfyKY7Gei36u8XQksgBJeNG4VvDzjc vCBX/sWEtIMUvYAZjF2hNPw= X-Google-Smtp-Source: AGHT+IF7eNZyraXuO05hd8ytRheYwAzq+Ufexzu1jhBvvkvtptakGZkXMw0wjg28+ew3AtHwCHepOQ== X-Received: by 2002:ac2:5594:0:b0:505:6eef:cf2d with SMTP id v20-20020ac25594000000b005056eefcf2dmr8118591lfg.17.1698153160957; Tue, 24 Oct 2023 06:12:40 -0700 (PDT) Received: from eldfell ([194.136.85.206]) by smtp.gmail.com with ESMTPSA id g3-20020a056512118300b005079dac9620sm2128423lfr.43.2023.10.24.06.12.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Oct 2023 06:12:40 -0700 (PDT) Date: Tue, 24 Oct 2023 16:12:34 +0300 From: Pekka Paalanen To: Ville =?UTF-8?B?U3lyasOkbMOk?= Subject: Re: [PATCH] drm/doc: describe PATH format for DP MST Message-ID: <20231024161234.4b35230b@eldfell> In-Reply-To: References: <20231023203629.198109-1-contact@emersion.fr> <20231024103604.6dd7f6d5@eldfell> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/hUEM7WlJTsPO0tmER0QbpSP"; protocol="application/pgp-signature"; micalg=pgp-sha256 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: , Cc: Dmitry Baryshkov , wayland-devel@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Daniel Vetter Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" --Sig_/hUEM7WlJTsPO0tmER0QbpSP Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tue, 24 Oct 2023 16:03:27 +0300 Ville Syrj=C3=A4l=C3=A4 wrote: > On Tue, Oct 24, 2023 at 09:03:22AM +0000, Simon Ser wrote: > > On Tuesday, October 24th, 2023 at 09:36, Pekka Paalanen wrote: > > =20 > > > Are DP MST port numbers guaranteed to be tied to the physical hardware > > > configuration (e.g. how cables are connected) and therefore stable > > > across reboots? What about stable across kernel upgrades? > > >=20 > > > If I knew that, I could perhaps manufacture a stable identifier in > > > userspace by replacing the parent connector ID with a stable connector > > > designator. =20 > >=20 > > Hm, my assumption is that these are stable, but maybe that's also wrong? > > Ville, Dmitry, do you know whether the DP MST port numbers are > > guaranteed stable across reboots when retaining the exact same hardware > > configuration (not the software, maybe the user upgraded the kernel)? = =20 >=20 > I suspect in practice those should remain the same as long as the > topology didn't change, but I don't think there's anything in the > DP spec that actually guarantees that (eg. some branch device > could in theory reshuffle its port numbers on a whim). >=20 > But there is no stable identifier for the corresponding SST > connector anyway so I don't know what you would even do with > stable port numbers. You mean the index in the array of connectors exposed to userspace is not stable either for the root DP connector? KMS device bus path + connector array index for hardwired connectors is what I've been imagining as stable enough for all end users. Thanks, pq --Sig_/hUEM7WlJTsPO0tmER0QbpSP Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEJQjwWQChkWOYOIONI1/ltBGqqqcFAmU3wsMACgkQI1/ltBGq qqeItw//X0o2L3AkG30OLXGZQIL5RF6CsCzA8seny7CqXu2nMQtfWTbEtbbavz3l BpNmnSKOMjk8kn0T1EMFhdHuA2Sophrnj2/fU5Ysn1aTlIminBWhIj6YkkvoBklE 4yvRj/yOsFft//zxGK7tnp7K8N4AnYu/RjwESReJ3MPx5r+21pL5RHcHiMp2BHII IwzncueXXqxTVXxD+GUTB72BPm9m2zc/Tk9+DxV2hr2EWiTZRuP9aEgE1TwBTxjM v9BLUsQld1Luc6w3xomeKCpkHdXHEcfg0XpG3D6TJAci7wtzkDtel3TMeKetG0yb na5RQFMDopzhtNnZy/XdpMLWuPWuoP6TH8OKfLYCIXX2pL7NE6Cq8hBo3WPUtUzp eq9v3EB/gzN5W0W5qWsCITWlnKuCjleeic3O42+J+zMceZYRy6qrYliVDKIEw9av RUV4oLHDdo1HusGKrckxiNUfcviAK3BS5p4lShWK8TZuWMe8Jx6LODEHDNxLKVo+ VHZD/xecZIbjPgCKmVrMrHMWrQ0eFc92C9NJG0pxHyuA6NcnqFNLnmUzoMwIXuWf AC2MbCZRHDlzCvvu//gaflQwIocfapUiXWa+AJZ1PuHbxgzaFeB4GXVJhSas0Gds CvxLGo14KUnUOjWn5uyMixx6aNqV/7SNtLlVb9tR1G5BO+uMWMo= =MVDN -----END PGP SIGNATURE----- --Sig_/hUEM7WlJTsPO0tmER0QbpSP--