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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 84463C43461 for ; Tue, 8 Sep 2020 10:03:12 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 4169E2078B for ; Tue, 8 Sep 2020 10:03:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="oxVqgMiZ"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KY0mlZUd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4169E2078B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe :List-Id:In-Reply-To:MIME-Version:References:Message-ID:Subject:To:From:Date: Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Fyct22LwN5UHiZpuokiNIPx082ducAibi/QQRZsOCoQ=; b=oxVqgMiZ/2GwSGaqgpdELtE9I7 +HVoWCnyXASuuLt9Or86Z5ScvVGNsdVddAaM7I+5RHK6Z62BjKdV/2G9lkLujGbxLtNb883lpes1M SJV8bbfjmWD6ZtoDqgUDHES7in9uEdwxoh4+XVDv52xOif5QuSY2DaW14mCnrsXTgk283UVNzew8S 3Dbj5QMuuS03n1khk4Iy4YfxJQs7+4mSII6UOvIMNgeSSGosBHAhgEJeJORq596NY34DigPJEb/T3 7qt41MvjZUEXrTaUsXNmiTJGmmvMaDWmoVafNhutMbYV+IZkLILFRnJ59yd6PlfsSjCsFfiBicx2S tLJuoJKA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFaSx-0004uw-Sc; Tue, 08 Sep 2020 10:03:07 +0000 Received: from us-smtp-1.mimecast.com ([207.211.31.81] helo=us-smtp-delivery-1.mimecast.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFaSt-0004tl-Fk for linux-rockchip@lists.infradead.org; Tue, 08 Sep 2020 10:03:04 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599559382; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Al+jB21s8k4aRrKK14DGG1BWv7CsWudzcU2+kAwpAVw=; b=KY0mlZUdf9re4ZotciWBlsAoGXgHn9eQG/tIjn/TSJhlLSoKFAjK6yYvT8j3bQhg8B83wa Rl3TgUAW9LAsNtN6rxERxAGSSq59rKvg2ZJ3Pz6Nyr44K0PENeyhZq5NMRGAWYUvVOMrou 0xnvuWUCIagoFkakg3ihCwKNn30GMVg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-37-22mgQBftORuwdHZCpB_IfA-1; Tue, 08 Sep 2020 06:02:59 -0400 X-MC-Unique: 22mgQBftORuwdHZCpB_IfA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CA3531091060; Tue, 8 Sep 2020 10:02:55 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-112-56.ams2.redhat.com [10.36.112.56]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9C75B1002388; Tue, 8 Sep 2020 10:02:54 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id ACCE89D78; Tue, 8 Sep 2020 12:02:53 +0200 (CEST) Date: Tue, 8 Sep 2020 12:02:53 +0200 From: Gerd Hoffmann To: dri-devel , Christian =?utf-8?B?S8O2bmln?= , Alex Deucher , David Airlie , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Lucas Stach , Russell King , Christian Gmeiner , Rob Clark , Sean Paul , Ben Skeggs , Sandy Huang , Heiko =?utf-8?Q?St=C3=BCbner?= , Thierry Reding , Jonathan Hunter , Oleksandr Andrushchenko , "open list:RADEON and AMDGPU DRM DRIVERS" , open list , "moderated list:DRM DRIVERS FOR VIVANTE GPU IP" , "open list:DRM DRIVER FOR MSM ADRENO GPU" , "open list:DRM DRIVER FOR MSM ADRENO GPU" , "open list:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS" , "moderated list:ARM/Rockchip SoC support" , "open list:ARM/Rockchip SoC support" , "open list:DRM DRIVERS FOR NVIDIA TEGRA" , "moderated list:DRM DRIVERS FOR XEN" Subject: Re: [PATCH v4 1/1] drm: allow limiting the scatter list size. Message-ID: <20200908100253.b22sff23737l77bo@sirius.home.kraxel.org> References: <20200907112425.15610-1-kraxel@redhat.com> <20200907112425.15610-2-kraxel@redhat.com> <20200908054858.um34wojjv6uhi7d3@sirius.home.kraxel.org> <20200908085544.GI2352366@phenom.ffwll.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200908085544.GI2352366@phenom.ffwll.local> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200908_060303_581299_AD758862 X-CRM114-Status: GOOD ( 17.46 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org > > > The comments I've found suggest very much not ... Or is that all very > > > old stuff only that no one cares about anymore? > > > > I think these days it is possible to override dma_ops per device, which > > in turn allows virtio to deal with the quirks without the rest of the > > kernel knowing about these details. > > > > I also think virtio-gpu can drop the virtio_has_dma_quirk() checks, just > > use the dma api path unconditionally and depend on virtio core having > > setup dma_ops in a way that it JustWorks[tm]. I'll look into that next. > > The comment above vring_use_dma_api() suggests that this has not yet > happened, that's why I'm asking. Hmm, wading through the code, seems it indeed happen yet, even though my testing didn't show any issues. Probably pure luck because devices and cpus have the same memory view on x86. Guess I need to try this on ppc64 to see it actually failing ... So dropping the virtio_has_dma_quirk() checks isn't going to fly. Using dma_max_mapping_size() should be fine though. It might use a lower limit than needed for virtio, but it should not break things. take care, Gerd _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip