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 X-Spam-Level: X-Spam-Status: No, score=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17942C433E0 for ; Wed, 27 Jan 2021 21:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC02964DD0 for ; Wed, 27 Jan 2021 21:29:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231448AbhA0V3Z (ORCPT ); Wed, 27 Jan 2021 16:29:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344491AbhA0V1g (ORCPT ); Wed, 27 Jan 2021 16:27:36 -0500 Received: from mail-lf1-x12c.google.com (mail-lf1-x12c.google.com [IPv6:2a00:1450:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5E146C061573 for ; Wed, 27 Jan 2021 13:26:56 -0800 (PST) Received: by mail-lf1-x12c.google.com with SMTP id v24so4723516lfr.7 for ; Wed, 27 Jan 2021 13:26:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=PkkTYvfWyANciuqV75npJ/gFbUncXc5JjD+XYOH0VH8=; b=BoTOvXdu3swqZb2+lsk9WlhzPZXwfhI0WIxDCA1OMC3oHJSMsL1Zh31Dw1l3Zdxb4q MMN90OsKTnEdbi0aHFmA9tRnjbanvZU+JmL1+/GLsWujC2m5oxLBaS9EUv44CgxaXTsX zFOVDhw+I7SE5LIVzDMgnhED4Kx/zqvWwwpCTqSfJvbBLg9ZsVPPJPuuKIxMWFHkUnAu 5Iv9e80z+3WGVPpj5FAFTn7k3RaSbMc6fmyxTe29aAln4dwrjABSJ/0h/8Hba5eEX2zz vwFrXxIm2d9WTNUuXgfFAdgbO8ayBDEjiR2q0zHB48CBdtSyhL+4tLM6zdErCvdcEm+p vj3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=PkkTYvfWyANciuqV75npJ/gFbUncXc5JjD+XYOH0VH8=; b=ErYD0UNtLKp3rCv96Nq2iJH0/yu7Ne0jZ0XUyujzcFSSkDykxIb6kaLQC1oExg3YAW wrjm+JPqKuGy3aWz9F19icRJh8KlTD9Dw3/de2qr0f5rSpBd1UYy0jDe4wPkZUSZGycA T1iZT5S7zRRLS2hjrgZNWdmif3YUi3pwAmaw0od19gjCxY7quo9z1V8LWwwR1NfUS7ZQ easftReviMufy5ia1Qr3I55e+Rv+LGR/r92ak3MLguD8RXuAgNCy6x1lbApu+gQWvxdO sEZpMyBGu01Zb1Ca+YE8y667yJePc5hrOw+4EWJ127KTSKiJpx5IUlExzOsmzcpiSGQ0 6O9w== X-Gm-Message-State: AOAM532UAOCEFQ5o2oFXPd4LCqxoOwuEKXQAuSz02LjwKvIHvLR5Qeg3 F1xMQuC90+mm0hl/Wgh4rdY= X-Google-Smtp-Source: ABdhPJwMOh5Zbzn5jlQDDiionvaHND6cl6YEMpkKIEYnDhyiUHbvJwqooKTYa8uuAqSnKJskJJ6wiQ== X-Received: by 2002:ac2:4907:: with SMTP id n7mr3247719lfi.213.1611782814893; Wed, 27 Jan 2021 13:26:54 -0800 (PST) Received: from ?IPv6:2a00:1370:814d:ea25:a10:76ff:fe69:21b6? ([2a00:1370:814d:ea25:a10:76ff:fe69:21b6]) by smtp.googlemail.com with ESMTPSA id b18sm823875lfj.140.2021.01.27.13.26.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 27 Jan 2021 13:26:54 -0800 (PST) Subject: Re: [PATCH v5 00/21] Host1x/TegraDRM UAPI To: Mikko Perttunen , Mikko Perttunen , thierry.reding@gmail.com, jonathanh@nvidia.com, airlied@linux.ie, daniel@ffwll.ch Cc: linux-tegra@vger.kernel.org, dri-devel@lists.freedesktop.org, talho@nvidia.com, bhuntsman@nvidia.com References: <20210111130019.3515669-1-mperttunen@nvidia.com> <2f999b6d-d781-503a-78f4-d444bce72c58@kapsi.fi> From: Dmitry Osipenko Message-ID: <638c1aeb-921b-0ea2-5258-16c6d3183306@gmail.com> Date: Thu, 28 Jan 2021 00:26:53 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.2 MIME-Version: 1.0 In-Reply-To: <2f999b6d-d781-503a-78f4-d444bce72c58@kapsi.fi> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org 26.01.2021 05:45, Mikko Perttunen пишет: >> 5. The hardware state of sync points should be reset when sync point is >> requested, not when host1x driver is initialized. > > This may be doable, but I don't think it is critical for this UAPI, so > let's consider it after this series. > > The userspace should anyway not be able to assume the initial value of > the syncpoint upon allocation. The kernel should set it to some high > value to catch any issues related to wraparound. This is critical because min != max when sync point is requested. > Also, this makes code more complicated since it now needs to ensure all > waits on the syncpoint have completed before freeing the syncpoint, > which can be nontrivial e.g. if the waiter is in a different virtual > machine or some other device connected via PCIe (a real usecase). It sounds to me that these VM sync points should be treated very separately from a generic sync points, don't you think so? Let's not mix them and get the generic sync points usable first.