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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 C3A8CC33CAA for ; Mon, 20 Jan 2020 10:48:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9978B207E0 for ; Mon, 20 Jan 2020 10:48:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SiYe/o08" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726635AbgATKsI (ORCPT ); Mon, 20 Jan 2020 05:48:08 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:50675 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726417AbgATKsI (ORCPT ); Mon, 20 Jan 2020 05:48:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579517286; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PJbVKql0qoMPmzm77SluaDLF6t/9vPquBMgRpCok4Fw=; b=SiYe/o08CCUfhL5XPW2R56XpujoUX5O5UmLkzJhhiFULk3FrFptCl8lJrMvGfUQLHH3YpE PJTN5W+YEU09oHrfJX8hkl01hCauwj1556hu3OIU/8YywZidkx/S4MSIC7dGPT4StvcCIW vWSKR2kL3pnKgML/jS03i1jTHDgkBMg= 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-395--7ImMQjkP5CpcQscamrOVw-1; Mon, 20 Jan 2020 05:48:03 -0500 X-MC-Unique: -7ImMQjkP5CpcQscamrOVw-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 42A0918A6EC3; Mon, 20 Jan 2020 10:48:00 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-116-106.ams2.redhat.com [10.36.116.106]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9FADE10013A7; Mon, 20 Jan 2020 10:47:56 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id D1CA316E36; Mon, 20 Jan 2020 11:47:55 +0100 (CET) Date: Mon, 20 Jan 2020 11:47:55 +0100 From: Gerd Hoffmann To: Keiichi Watanabe Cc: Tomasz Figa , Dmitry Sepp , spice-devel@lists.freedesktop.org, virtio-dev@lists.oasis-open.org, Linux Media Mailing List , Alexandre Courbot , Alex Lau , Daniel Vetter , Dylan Reid , Enrico Granata , Frediano Ziglio , Hans Verkuil , =?utf-8?B?U3TDqXBoYW5l?= Marchesin , Pawel Osciak , David Stevens , uril@redhat.com Subject: Re: [virtio-dev] Re: [PATCH v2 0/1] VirtIO video device specification Message-ID: <20200120104755.3hhxlx6x6o32bagf@sirius.home.kraxel.org> References: <20191218130214.170703-1-keiichiw@chromium.org> <7740094.NyiUUSuA9g@os-lin-dmo> <20200113095636.blov62o4gbf27om5@sirius.home.kraxel.org> <12433898.dW097sEU6C@os-lin-dmo> <20200113110521.5ogc3fcy4zq32yzg@sirius.home.kraxel.org> <20200113132654.r4lhspfx2z7zse2v@sirius.home.kraxel.org> <20200115112640.52kemwg4lncuvvir@sirius.home.kraxel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi, > > Hmm, using (ii) the API, then check whenever your three plane buffers > > happen to have the correct layout for (1) hardware looks somewhat > > backwards to me. > > Can't this problem be solved by adding "offset" field in virtio_video_mem_entry? > > struct virtio_video_mem_entry { > le64 addr; > le32 length; > le32 offset; > u8 padding[4]; > }; > > Here, "addr" must be the same in every mem_entry for (1) hardware. No. virtio_video_mem_entry is basically a scatter list entry, you use an *array* of these entries to describe your buffer (unless you are using CMA due to hardware requirements, in this special case you have only one entry in your array). > > I'd suggest to use (i) API and allow the device specify alignment > > requirements. So (1) hardware would say "need_align=0", whereas (3) > > hardware would probably say "need_align=PAGE_SIZE" so it can easily > > split the single buffer into three per-plane buffers. > > Just to confirm, is "need_align" a field added in virtio_video_format_desc? Given that different formats might have different alignment requirements this looks like a good place to me. Maybe rename to plane_align to make clear what kind of alignment this is. cheers, Gerd From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-6667-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id D5E87985DF6 for ; Mon, 20 Jan 2020 10:48:10 +0000 (UTC) Date: Mon, 20 Jan 2020 11:47:55 +0100 From: Gerd Hoffmann Message-ID: <20200120104755.3hhxlx6x6o32bagf@sirius.home.kraxel.org> References: <20191218130214.170703-1-keiichiw@chromium.org> <7740094.NyiUUSuA9g@os-lin-dmo> <20200113095636.blov62o4gbf27om5@sirius.home.kraxel.org> <12433898.dW097sEU6C@os-lin-dmo> <20200113110521.5ogc3fcy4zq32yzg@sirius.home.kraxel.org> <20200113132654.r4lhspfx2z7zse2v@sirius.home.kraxel.org> <20200115112640.52kemwg4lncuvvir@sirius.home.kraxel.org> MIME-Version: 1.0 In-Reply-To: Subject: Re: [virtio-dev] Re: [PATCH v2 0/1] VirtIO video device specification Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline To: Keiichi Watanabe Cc: Tomasz Figa , Dmitry Sepp , spice-devel@lists.freedesktop.org, virtio-dev@lists.oasis-open.org, Linux Media Mailing List , Alexandre Courbot , Alex Lau , Daniel Vetter , Dylan Reid , Enrico Granata , Frediano Ziglio , Hans Verkuil , =?utf-8?B?U3TDqXBoYW5l?= Marchesin , Pawel Osciak , David Stevens , uril@redhat.com List-ID: Hi, > > Hmm, using (ii) the API, then check whenever your three plane buffers > > happen to have the correct layout for (1) hardware looks somewhat > > backwards to me. >=20 > Can't this problem be solved by adding "offset" field in virtio_video_mem= _entry? >=20 > struct virtio_video_mem_entry { > le64 addr; > le32 length; > le32 offset; > u8 padding[4]; > }; >=20 > Here, "addr" must be the same in every mem_entry for (1) hardware. No. virtio_video_mem_entry is basically a scatter list entry, you use an *array* of these entries to describe your buffer (unless you are using CMA due to hardware requirements, in this special case you have only one entry in your array). > > I'd suggest to use (i) API and allow the device specify alignment > > requirements. So (1) hardware would say "need_align=3D0", whereas (3) > > hardware would probably say "need_align=3DPAGE_SIZE" so it can easily > > split the single buffer into three per-plane buffers. >=20 > Just to confirm, is "need_align" a field added in virtio_video_format_des= c? Given that different formats might have different alignment requirements this looks like a good place to me. Maybe rename to plane_align to make clear what kind of alignment this is. cheers, Gerd --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org