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=-13.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 7386BC4338F for ; Wed, 25 Aug 2021 01:17:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48CDF61163 for ; Wed, 25 Aug 2021 01:17:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236583AbhHYBRr (ORCPT ); Tue, 24 Aug 2021 21:17:47 -0400 Received: from alexa-out.qualcomm.com ([129.46.98.28]:11927 "EHLO alexa-out.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230124AbhHYBRq (ORCPT ); Tue, 24 Aug 2021 21:17:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1629854221; x=1661390221; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=Ppczo/0UhEqduN9raiNIidj5suITutz6sSUsUlr93xI=; b=GsFz7myoAb9tOtr6+/B2xw6w4ALRAuRqaTxtTxZcGolWDjHekOZwFQG4 JFn4JE1PvAf8EoZ7Q4YNIyjpYYmhBa5FeNlrhOV5/6O3aqSVzsWeMsOWp QwGioePmm0dgj7h68KiVCI2GiYfqKTXDdu+ow6RCh+WSmMqKSjQAuECcc 8=; Received: from ironmsg-lv-alpha.qualcomm.com ([10.47.202.13]) by alexa-out.qualcomm.com with ESMTP; 24 Aug 2021 18:17:01 -0700 X-QCInternal: smtphost Received: from nalasex01a.na.qualcomm.com ([10.47.209.196]) by ironmsg-lv-alpha.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 18:17:00 -0700 Received: from [10.226.59.216] (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.922.7; Tue, 24 Aug 2021 18:16:59 -0700 Subject: Re: [git pull] habanalabs pull request for kernel 5.15 To: Dave Airlie , Greg Kroah-Hartman , Jason Gunthorpe , Daniel Vetter , Linus Torvalds CC: Oded Gabbay , LKML References: <20210819110209.GA115485@ogabbay-vm2.habana-labs.com> From: Jeffrey Hugo Message-ID: <5506552d-5be1-42f6-ead5-51b92a7ced82@quicinc.com> Date: Tue, 24 Aug 2021 19:16:59 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/19/2021 12:48 PM, Dave Airlie wrote: > On Fri, 20 Aug 2021 at 03:07, Greg KH wrote: >> >> On Thu, Aug 19, 2021 at 02:02:09PM +0300, Oded Gabbay wrote: >>> Hi Greg, >>> >>> This is habanalabs pull request for the merge window of kernel 5.15. >>> The commits divide roughly 50/50 between adding new features, such >>> as peer-to-peer support with DMA-BUF or signaling from within a graph, >>> and fixing various bugs, small improvements, etc. >> >> Pulled and pushed out, thanks! > > NAK for adding dma-buf or p2p support to this driver in the upstream > kernel. There needs to be a hard line between > "I-can't-believe-its-not-a-drm-driver" drivers which bypass our > userspace requirements, and I consider this the line. > > This driver was merged into misc on the grounds it wasn't really a > drm/gpu driver and so didn't have to accept our userspace rules. > > Adding dma-buf/p2p support to this driver is showing it really fits > the gpu driver model and should be under the drivers/gpu rules since > what are most GPUs except accelerators. Care to elaborate? I'm not trying to be cute, but all I see here is that dma-buf/p2p using drivers must be in drivers/gpu, yet many drivers outside of the gpu area use those features. Surely your position can't be that only drivers/gpu can use dma-buf or p2p (which is part of the PCIe spec). > We are opening a major can of worms (some would say merging habanalabs > driver opened it), but this places us in the situation that if a GPU > vendor just claims their hw is a "vector" accelerator they can use > Greg to bypass all the work that been done to ensure we have > maintainability long term. I don't want drivers in the tree using > dma-buf to interact with other drivers when we don't have access to a > userspace project to validate the kernel driver assumptions. Umm, isn't that [1]? The Habana device has the most open userspace I'm aware of. Seems disingenuous to claim you don't have access to a userspace project for this driver. [1] - https://github.com/HabanaAI/hl-thunk