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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 D5418C433DB for ; Wed, 27 Jan 2021 21:58:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6B9F61488 for ; Wed, 27 Jan 2021 21:58:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234402AbhA0V6y (ORCPT ); Wed, 27 Jan 2021 16:58:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236114AbhA0V6J (ORCPT ); Wed, 27 Jan 2021 16:58:09 -0500 Received: from mail.kapsi.fi (mail.kapsi.fi [IPv6:2001:67c:1be8::25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0934C061573 for ; Wed, 27 Jan 2021 13:57:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=kapsi.fi; s=20161220; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=PFr1PpZ+sLDeYeNOkv4pXr/k0mA3n8rwWzFd2Ytw6Lk=; b=NKToiTco1g4RyKH+LeCBlLsyYE naKzRclnRvcNQX6hxIR06mB62WdAsk4MlUQQ0cr0UZOJB25ea0KoBM2VmWoc2CVWTR6IEdzKZN3BV TJupFHEm2z4LkE8NUOtFemn9BLi0jduBErcXoQ76a4YKnYGkk9btZK1YXnLfbEC/dKXwMqMqwd5rd p8Fz5jtXbotU/yCrpdSpfeKNVyezf3zXECdrANshBvNcgsQAvFC3GhzQqdeGyh23+zseLo2i2QY2b tJd7Uf7tGReTiMhifpjTl9ZRjI0N/TC4O9ZOZN14WaTVRK2959WXbnFjg1Jk3R8NT1QwSp5/YtN8w s0NbsVCw==; Received: from dsl-hkibng22-54f986-236.dhcp.inet.fi ([84.249.134.236] helo=[192.168.1.10]) by mail.kapsi.fi with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1l4soI-00086B-QU; Wed, 27 Jan 2021 23:57:10 +0200 Subject: Re: [PATCH v5 00/21] Host1x/TegraDRM UAPI To: Dmitry Osipenko , 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> <638c1aeb-921b-0ea2-5258-16c6d3183306@gmail.com> From: Mikko Perttunen Message-ID: <9f755e95-97fc-4f57-5e8d-426af589c857@kapsi.fi> Date: Wed, 27 Jan 2021 23:57:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <638c1aeb-921b-0ea2-5258-16c6d3183306@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 84.249.134.236 X-SA-Exim-Mail-From: cyndis@kapsi.fi X-SA-Exim-Scanned: No (on mail.kapsi.fi); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On 1/27/21 11:26 PM, Dmitry Osipenko wrote: > 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. That I would just consider a bug, and it can be fixed. But it's orthogonal to whether the value gets reset every time the syncpoint is allocated. > >> 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. > They are not special in any way, I'm just referring to cases where the waiter (consumer) is remote. The allocator of the syncpoint (producer) doesn't necessarily even need to know about it. The same concern is applicable within a single VM, or single application as well. Just putting out the point that this is something that needs to be taken care of if we were to reset the value. Mikko 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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 8E01AC433E0 for ; Wed, 27 Jan 2021 21:57:15 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 01D0D64DA3 for ; Wed, 27 Jan 2021 21:57:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01D0D64DA3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kapsi.fi Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 71C2B6E8B2; Wed, 27 Jan 2021 21:57:14 +0000 (UTC) Received: from mail.kapsi.fi (mail.kapsi.fi [IPv6:2001:67c:1be8::25]) by gabe.freedesktop.org (Postfix) with ESMTPS id 367C089BF1 for ; Wed, 27 Jan 2021 21:57:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=kapsi.fi; s=20161220; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=PFr1PpZ+sLDeYeNOkv4pXr/k0mA3n8rwWzFd2Ytw6Lk=; b=NKToiTco1g4RyKH+LeCBlLsyYE naKzRclnRvcNQX6hxIR06mB62WdAsk4MlUQQ0cr0UZOJB25ea0KoBM2VmWoc2CVWTR6IEdzKZN3BV TJupFHEm2z4LkE8NUOtFemn9BLi0jduBErcXoQ76a4YKnYGkk9btZK1YXnLfbEC/dKXwMqMqwd5rd p8Fz5jtXbotU/yCrpdSpfeKNVyezf3zXECdrANshBvNcgsQAvFC3GhzQqdeGyh23+zseLo2i2QY2b tJd7Uf7tGReTiMhifpjTl9ZRjI0N/TC4O9ZOZN14WaTVRK2959WXbnFjg1Jk3R8NT1QwSp5/YtN8w s0NbsVCw==; Received: from dsl-hkibng22-54f986-236.dhcp.inet.fi ([84.249.134.236] helo=[192.168.1.10]) by mail.kapsi.fi with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1l4soI-00086B-QU; Wed, 27 Jan 2021 23:57:10 +0200 Subject: Re: [PATCH v5 00/21] Host1x/TegraDRM UAPI To: Dmitry Osipenko , Mikko Perttunen , thierry.reding@gmail.com, jonathanh@nvidia.com, airlied@linux.ie, daniel@ffwll.ch References: <20210111130019.3515669-1-mperttunen@nvidia.com> <2f999b6d-d781-503a-78f4-d444bce72c58@kapsi.fi> <638c1aeb-921b-0ea2-5258-16c6d3183306@gmail.com> From: Mikko Perttunen Message-ID: <9f755e95-97fc-4f57-5e8d-426af589c857@kapsi.fi> Date: Wed, 27 Jan 2021 23:57:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <638c1aeb-921b-0ea2-5258-16c6d3183306@gmail.com> Content-Language: en-US X-SA-Exim-Connect-IP: 84.249.134.236 X-SA-Exim-Mail-From: cyndis@kapsi.fi X-SA-Exim-Scanned: No (on mail.kapsi.fi); SAEximRunCond expanded to false 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: linux-tegra@vger.kernel.org, talho@nvidia.com, bhuntsman@nvidia.com, dri-devel@lists.freedesktop.org Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" CgpPbiAxLzI3LzIxIDExOjI2IFBNLCBEbWl0cnkgT3NpcGVua28gd3JvdGU6Cj4gMjYuMDEuMjAy MSAwNTo0NSwgTWlra28gUGVydHR1bmVuINC/0LjRiNC10YI6Cj4+PiA1LiBUaGUgaGFyZHdhcmUg c3RhdGUgb2Ygc3luYyBwb2ludHMgc2hvdWxkIGJlIHJlc2V0IHdoZW4gc3luYyBwb2ludCBpcwo+ Pj4gcmVxdWVzdGVkLCBub3Qgd2hlbiBob3N0MXggZHJpdmVyIGlzIGluaXRpYWxpemVkLgo+Pgo+ PiBUaGlzIG1heSBiZSBkb2FibGUsIGJ1dCBJIGRvbid0IHRoaW5rIGl0IGlzIGNyaXRpY2FsIGZv ciB0aGlzIFVBUEksIHNvCj4+IGxldCdzIGNvbnNpZGVyIGl0IGFmdGVyIHRoaXMgc2VyaWVzLgo+ Pgo+PiBUaGUgdXNlcnNwYWNlIHNob3VsZCBhbnl3YXkgbm90IGJlIGFibGUgdG8gYXNzdW1lIHRo ZSBpbml0aWFsIHZhbHVlIG9mCj4+IHRoZSBzeW5jcG9pbnQgdXBvbiBhbGxvY2F0aW9uLiBUaGUg a2VybmVsIHNob3VsZCBzZXQgaXQgdG8gc29tZSBoaWdoCj4+IHZhbHVlIHRvIGNhdGNoIGFueSBp c3N1ZXMgcmVsYXRlZCB0byB3cmFwYXJvdW5kLgo+IAo+IFRoaXMgaXMgY3JpdGljYWwgYmVjYXVz ZSBtaW4gIT0gbWF4IHdoZW4gc3luYyBwb2ludCBpcyByZXF1ZXN0ZWQuCgpUaGF0IEkgd291bGQg anVzdCBjb25zaWRlciBhIGJ1ZywgYW5kIGl0IGNhbiBiZSBmaXhlZC4gQnV0IGl0J3MgCm9ydGhv Z29uYWwgdG8gd2hldGhlciB0aGUgdmFsdWUgZ2V0cyByZXNldCBldmVyeSB0aW1lIHRoZSBzeW5j cG9pbnQgaXMgCmFsbG9jYXRlZC4KCj4gCj4+IEFsc28sIHRoaXMgbWFrZXMgY29kZSBtb3JlIGNv bXBsaWNhdGVkIHNpbmNlIGl0IG5vdyBuZWVkcyB0byBlbnN1cmUgYWxsCj4+IHdhaXRzIG9uIHRo ZSBzeW5jcG9pbnQgaGF2ZSBjb21wbGV0ZWQgYmVmb3JlIGZyZWVpbmcgdGhlIHN5bmNwb2ludCwK Pj4gd2hpY2ggY2FuIGJlIG5vbnRyaXZpYWwgZS5nLiBpZiB0aGUgd2FpdGVyIGlzIGluIGEgZGlm ZmVyZW50IHZpcnR1YWwKPj4gbWFjaGluZSBvciBzb21lIG90aGVyIGRldmljZSBjb25uZWN0ZWQg dmlhIFBDSWUgKGEgcmVhbCB1c2VjYXNlKS4KPiAKPiBJdCBzb3VuZHMgdG8gbWUgdGhhdCB0aGVz ZSBWTSBzeW5jIHBvaW50cyBzaG91bGQgYmUgdHJlYXRlZCB2ZXJ5Cj4gc2VwYXJhdGVseSBmcm9t IGEgZ2VuZXJpYyBzeW5jIHBvaW50cywgZG9uJ3QgeW91IHRoaW5rIHNvPyBMZXQncyBub3QgbWl4 Cj4gdGhlbSBhbmQgZ2V0IHRoZSBnZW5lcmljIHN5bmMgcG9pbnRzIHVzYWJsZSBmaXJzdC4KPiAK ClRoZXkgYXJlIG5vdCBzcGVjaWFsIGluIGFueSB3YXksIEknbSBqdXN0IHJlZmVycmluZyB0byBj YXNlcyB3aGVyZSB0aGUgCndhaXRlciAoY29uc3VtZXIpIGlzIHJlbW90ZS4gVGhlIGFsbG9jYXRv ciBvZiB0aGUgc3luY3BvaW50IChwcm9kdWNlcikgCmRvZXNuJ3QgbmVjZXNzYXJpbHkgZXZlbiBu ZWVkIHRvIGtub3cgYWJvdXQgaXQuIFRoZSBzYW1lIGNvbmNlcm4gaXMgCmFwcGxpY2FibGUgd2l0 aGluIGEgc2luZ2xlIFZNLCBvciBzaW5nbGUgYXBwbGljYXRpb24gYXMgd2VsbC4gSnVzdCAKcHV0 dGluZyBvdXQgdGhlIHBvaW50IHRoYXQgdGhpcyBpcyBzb21ldGhpbmcgdGhhdCBuZWVkcyB0byBi ZSB0YWtlbiBjYXJlIApvZiBpZiB3ZSB3ZXJlIHRvIHJlc2V0IHRoZSB2YWx1ZS4KCk1pa2tvCl9f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmRyaS1kZXZlbCBt YWlsaW5nIGxpc3QKZHJpLWRldmVsQGxpc3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3Rz LmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2RyaS1kZXZlbAo=