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,DKIM_INVALID, DKIM_SIGNED,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 5BA20C433E1 for ; Fri, 14 Aug 2020 17:25:32 +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 C87B420708 for ; Fri, 14 Aug 2020 17:25:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="TT08nnIc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C87B420708 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch 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 A9C4B6EB9D; Fri, 14 Aug 2020 17:25:30 +0000 (UTC) Received: from mail-ot1-x330.google.com (mail-ot1-x330.google.com [IPv6:2607:f8b0:4864:20::330]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6A6556EB9C for ; Fri, 14 Aug 2020 17:25:29 +0000 (UTC) Received: by mail-ot1-x330.google.com with SMTP id t7so8177233otp.0 for ; Fri, 14 Aug 2020 10:25:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Y+BjmX7YUnKQpYU9vXERFMaofOWtD1Q2eOk/KhoCNmE=; b=TT08nnIcVbkonBU2cP1uTcHNOmEoYklbwVkA6OZ9jKg2Y0Z1pqPUo9Gm2zuQqGH9uG dG1yOsqG0bbxoc9seu4w6A2Qrwtgbn92CchnZpSh4sPo3lGIPmADddXHBf52k+XqSzcS ka3WpGV10GCWrv9MNwOuO3M/cSHsVcc6n31MI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Y+BjmX7YUnKQpYU9vXERFMaofOWtD1Q2eOk/KhoCNmE=; b=NQitYh3HA0YzAGMhRsu7IM31dhibGId6/36HRIirg2xqzvJIJBhbnAMzXzslMPm1xV /rBQfs8itWvmEq5ALZRORJoRlulVkrMKzD+MLnFNllP3EicRL974GYkumRldGJa5sY22 CqCbP7URE930w97hfezUhdnbVa8L9r4kUv/1Duq5yKAbc/kLueab/+nsByHNTCx+S+/6 8Y8ZicfrtX4+YwFQ/p1MpsA2kwTJS94+KhZ6cJodD26RVM6IXBEtX2p015HWgw+38fnX ZpQ6696NCv6/GXDiHiXQO8hVTw+wHGrL4B6vn1BXS5dyIQoDmjVaPltvsEI5DYMKQQ+k 6s/g== X-Gm-Message-State: AOAM530q72xMNgmEnk2wIcISum7yINVm4H/rvArLPDC2c9jr1iNUddbD 4Qvz1M02WHiNtLxLSpgkZEpMm89VIJ3LRh/Pv34YnA== X-Google-Smtp-Source: ABdhPJyX1924BAPToUhlvSDL8ajd7s7minqNKnBdt5FhFW2FKNF4oMDhMDFIxfesqgMk3FvD3ZzleiKT0f74zjMXUjc= X-Received: by 2002:a05:6830:1e71:: with SMTP id m17mr2805714otr.188.1597425928661; Fri, 14 Aug 2020 10:25:28 -0700 (PDT) MIME-Version: 1.0 References: <20200814140527.GD556087@ulmo> <20200814153449.GH556087@ulmo> <20200814160631.GI556087@ulmo> <20200814162210.GA611027@ulmo> In-Reply-To: From: Daniel Vetter Date: Fri, 14 Aug 2020 19:25:17 +0200 Message-ID: Subject: Re: [git pull] drm for 5.8-rc1 To: Daniel Stone 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: Karol Herbst , James Jones , dri-devel , Thierry Reding , Alyssa Rosenzweig , Thierry Reding Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Fri, Aug 14, 2020 at 7:17 PM Daniel Stone wrote: > > Hi, > > On Fri, 14 Aug 2020 at 17:22, Thierry Reding wrote: > > I suspect that the reason why this works in X but not in Wayland is > > because X passes the right usage flags, whereas Weston may not. But I'll > > have to investigate more in order to be sure. > > Weston allocates its own buffers for displaying the result of > composition through GBM with USE_SCANOUT, which is definitely correct. > > Wayland clients (common to all compositors, in Mesa's > src/egl/drivers/dri2/platform_wayland.c) allocate with USE_SHARED but > _not_ USE_SCANOUT, which is correct in that they are guaranteed to be > shared, but not guaranteed to be scanned out. The expectation is that > non-scanout-compatible buffers would be rejected by gbm_bo_import if > not drmModeAddFB2. > > One difference between Weston and all other compositors (GNOME Shell, > KWin, Sway, etc) is that Weston uses KMS planes for composition when > it can (i.e. when gbm_bo_import from dmabuf + drmModeAddFB2 from > gbm_bo handle + atomic check succeed), but the other compositors only > use the GPU. So if you have different assumptions about the layout of > imported buffers between the GPU and KMS, that would explain a fair > bit. Yeah non-modifiered multi-gpu (of any kind) is pretty much hopeless I think. I guess the only option is if the tegra mesa driver forces linear and an extra copy on everything that's USE_SHARED or USE_SCANOUT. > > Perhaps we can go and release X 1.21.0 with that modifier enablement > > patch and that'll motivate desktops to adopt it as well as the default? > > Unfortunately we don't really have a good way out of this one. They > were disabled because the non-modifier path on Intel can be linear or > X-tiled (row-major), whereas the modifier path enables Y-tiled > (column-major) and compressed layouts. Y-tiled is the most efficient, > but Intel could only spare about six transistors for the global FIFO > shared between all their plane fetch engines, and Y-tiled blows > straight through it. Both X and Shell would thus fail to enable high > resolutions or many heads (2x 4K is enough even on modern platforms > IIRC), so they just turned modifiers off. > > The best solution would be to do a global atomic_check across all > outputs and just blacklist modifiers until you find one which works, > but Shell doesn't yet have that code, and -modesetting ... well, > no-one's volunteered to do that yet, or probably ever. Yeah best bet for modifiered X is Xwayland on top of weston right now :-/ -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel