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 97C9DC32772 for ; Tue, 16 Aug 2022 19:56:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236227AbiHPT4C (ORCPT ); Tue, 16 Aug 2022 15:56:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236924AbiHPT4B (ORCPT ); Tue, 16 Aug 2022 15:56:01 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7AB6779604; Tue, 16 Aug 2022 12:56:00 -0700 (PDT) Received: from [192.168.2.145] (109-252-119-13.nat.spd-mgts.ru [109.252.119.13]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by madras.collabora.co.uk (Postfix) with ESMTPSA id 2BC5C660037D; Tue, 16 Aug 2022 20:55:57 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1660679758; bh=QUXUXYkhFymxKXOLeAezfOww+02sMdDSnE//u2RiUFM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=CVM4id76n+RhaUefcyoNI4yah3kDGdYyN68LKYUcBxQy6kRNp16EuhrcSBTm7BxN/ 1okQMK8mg83NetPZXjRBPYQr5xe5pPctN7Tj8kWrJ0Ed8Jk6E8SEd1Y9qLJGJg6VMI ANvZj/dqHo84JivmR8Qr0MnboYLog7JlWO+nVEjy9HhMEBIF2XF8frWBlcS//ZuwCq dMbGTF2wy1/70Skx2C9muNyZTNkW95vijAHW4X7/8tzDHWiQj+b71rvCL+p7P/6BdL qNqkAVP0hp6clTF16+kJXWqby9L2e5++00yZavOGTJ8VEiQ383euMrJUgzyhkHSiII SDR3f8LvCxx0Q== Message-ID: Date: Tue, 16 Aug 2022 22:55:52 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Subject: Re: [PATCH v8 2/2] drm/gem: Don't map imported GEMs Content-Language: en-US To: =?UTF-8?Q?Christian_K=c3=b6nig?= , Rob Clark , =?UTF-8?Q?Christian_K=c3=b6nig?= Cc: David Airlie , Gerd Hoffmann , Gurchetan Singh , Chia-I Wu , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Emil Velikov , =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= , Linux Kernel Mailing List , dri-devel , "open list:VIRTIO GPU DRIVER" , linux-tegra@vger.kernel.org, Dmitry Osipenko , kernel@collabora.com, Daniel Vetter References: <20220701090240.1896131-1-dmitry.osipenko@collabora.com> <20220701090240.1896131-3-dmitry.osipenko@collabora.com> <2bb95e80-b60a-36c0-76c8-a06833032c77@amd.com> <2a646ce4-c2ec-3b11-77a0-cc720afd6fe1@collabora.com> <9674d00e-c0d6-ceba-feab-5dc475bda694@collabora.com> <73b51dde-689f-64ce-a1c8-0d7c84a2ed66@collabora.com> <5f118e10-db7a-a128-1e87-c9dddb65b2ac@collabora.com> <2ce5ff0a-9ab2-d146-04db-487a64714fce@gmail.com> From: Dmitry Osipenko In-Reply-To: <2ce5ff0a-9ab2-d146-04db-487a64714fce@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/16/22 15:03, Christian König wrote: > Am 16.08.22 um 13:44 schrieb Dmitry Osipenko: >> [SNIP] >>> The other complication I noticed is that we don't seem to keep around >>> the fd after importing to a GEM handle.  And I could imagine that >>> doing so could cause issues with too many fd's.  So I guess the best >>> thing is to keep the status quo and let drivers that cannot mmap >>> imported buffers just fail mmap? >> That actually should be all the drivers excluding those that use >> DRM-SHMEM because only DRM-SHMEM uses dma_buf_mmap(), that's why it >> works for Panfrost. I'm pretty sure mmaping of imported GEMs doesn't >> work for the MSM driver, isn't it? >> >> Intel and AMD drivers don't allow to map the imported dma-bufs. Both >> refuse to do the mapping. >> >> Although, AMDGPU "succeeds" to do the mapping using >> AMDGPU_GEM_DOMAIN_GTT, but then touching the mapping causes bus fault, >> hence mapping actually fails. I think it might be the AMDGPU >> driver/libdrm bug, haven't checked yet. > > That's then certainly broken somehow. Amdgpu should nerve ever have > allowed to mmap() imported DMA-bufs and the last time I check it didn't. I'll take a closer look. So far I can only tell that it's a kernel driver issue because once I re-applied this "Don't map imported GEMs" patch, AMDGPU began to refuse mapping AMDGPU_GEM_DOMAIN_GTT. >> So we're back to the point that neither of DRM drivers need to map >> imported dma-bufs and this was never tested. In this case this patch is >> valid, IMO. Actually, I'm now looking at Etnaviv and Nouveau and seems they should map imported dma-buf properly. I know that people ran Android on Etnaviv. So maybe devices with a separated GPU/display need to map imported display BO for Android support. Wish somebody who ran Android on one of these devices using upstream drivers could give a definitive answer. I may try to test Nouveau later on. -- Best regards, Dmitry