From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-x233.google.com (mail-io0-x233.google.com [IPv6:2607:f8b0:4001:c06::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id EA36C2095B9C6 for ; Thu, 24 Aug 2017 05:22:58 -0700 (PDT) Received: by mail-io0-x233.google.com with SMTP id p70so1609932iod.0 for ; Thu, 24 Aug 2017 05:25:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=LhL1FSvSBA8dzpxe59e663RyZb11zBlwK4g9jZWDVsM=; b=WuorHr3/099Sm3O6w7n6rl0FAcghO2lhyHaXLc2erJtmYV+yseF5RlRa6G7RHai0WD dQFRnJIuK7XZ2hkhjRgArB4UcGzLD83sB9HBw4lWU6N8gZTPEIiI4w0mSBGnxM9DqJvy Dj+KQpAm7G8/+0tCmXtCW/ztBRZ0oQQaZHoC8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=LhL1FSvSBA8dzpxe59e663RyZb11zBlwK4g9jZWDVsM=; b=WIF8t/xQh3K6EeDkQdFjPd2cfgOaObAqBpTM+xpt7F/5HOR+jZfkKgodS1rzS4e2HV 3Pqc1DvApJZHIUDueG3MeWTL2kRd9z3cexXsBOPnc1R3Mf4rjDS7M3/Ouj2N3SYb04Wm uECv6KubYAMD4ekLKb+5ceQyss0DI9IwOpItKKsVxb2NHzFSJenEPYF6BPKPYwX4LED4 891tBusgZ1nRTPctLgqLR9QAoAJg/kfySMGGQkhJFrXa/K+z4XijS2EProg6nMyKKtjW EIG6pY1PtktXkjI0RgJCuJsazU7HoTquld5t4uI687VGnfsorbXiHERkrsm9S4cZLhH5 BdMg== X-Gm-Message-State: AHYfb5hH3Fd3e7AIoPp/WlwXOvYhTfVjaFfkywg0QNGfuh/hFUdLcVRq FH138fCjmnLjLR0Adkflv1IGkkL5d8S/ X-Received: by 10.107.6.22 with SMTP id 22mr4924050iog.190.1503577533038; Thu, 24 Aug 2017 05:25:33 -0700 (PDT) MIME-Version: 1.0 Received: by 10.107.162.1 with HTTP; Thu, 24 Aug 2017 05:25:32 -0700 (PDT) In-Reply-To: <20170824120226.g254d34ak3xam6qi@bivouac.eciton.net> References: <20170822163013.12233-1-ard.biesheuvel@linaro.org> <20170823131516.6f4d2p6jy222ch6m@bivouac.eciton.net> <97d8b88a-9583-2a53-7061-33e0351d622b@redhat.com> <20170823150057.mddgzpucjtbg3u3o@bivouac.eciton.net> <20170824120226.g254d34ak3xam6qi@bivouac.eciton.net> From: Ard Biesheuvel Date: Thu, 24 Aug 2017 13:25:32 +0100 Message-ID: To: Leif Lindholm Cc: Laszlo Ersek , "edk2-devel@lists.01.org" , Jordan Justen Subject: Re: [PATCH] ArmVirtPkg: remove QemuVideoDxe from ArmVirtQemu and ArmVirtQemuKernel X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Aug 2017 12:22:59 -0000 Content-Type: text/plain; charset="UTF-8" On 24 August 2017 at 13:02, Leif Lindholm wrote: > On Wed, Aug 23, 2017 at 04:00:57PM +0100, Leif Lindholm wrote: >> On Wed, Aug 23, 2017 at 03:36:37PM +0200, Laszlo Ersek wrote: >> > On 08/23/17 15:17, Ard Biesheuvel wrote: >> > >>>> (My R-b stands; these are comments for a possible followup patch.) >> > >>>> >> > >>>> Please see: >> > >>>> >> > >>>> - commit 84a75f70e903 ("OvmfPkg/QemuVideoDxe: enable ARM builds", >> > >>>> 2015-02-23), >> > >>>> >> > >>>> - commit 05a537945872 ("OvmfPkg/QemuVideoDxe: Helper functions for >> > >>>> unaligned port I/O.", 2017-04-07)? >> > >>>> >> > >>>> In my opinion, we should now revert parts of these commits, in one >> > >>>> followup patch: >> > >>>> >> > >>>> - from the first commit, we should revert only the "VALID_ARCHITECTURES" >> > >>>> comment change (the rest is built upon by the second commit, and should >> > >>>> be preserved) >> > >>>> >> > >>>> - from the second commit, we should revert the addition of [Sources.ARM, >> > >>>> Sources.AARCH64]. >> > >>>> >> > >>>> This boils down to removing ARM and AARCH64 references from the >> > >>>> QemuVideoDxe.inf file. If you agree, could you please submit such a >> > >>>> followup patch? >> > >>> >> > >>> Sure, but pending the graphical GRUB discussion. >> > >> >> > >> So, after looking at the GRUB code, I am leaning towards agreeing that >> > >> this is actually not a problem at all ... probably. The efi_gop driver >> > >> does a Blt() of the entire screen from an off-screen buffer for all >> > >> updates _unless_ it fails to allocate that off-screen buffer. >> > >> >> > >> So, basically, if you run out of memory at that point, it will try to >> > >> preserve a way to get messages out about that. I will send a question >> > >> out to grub-devel regarding this behaviour. >> > >> >> > >> However, looking at the specification, a question remains over how >> > >> software can determine whether direct FB access is possible. I mean, a >> > >> value of 0 seems like a decent hint, but the spec says nothing on the >> > >> topic. >> > >> >> > > >> > > It will assume the FB is accessible unless the pixel format is PixelBltOnly >> > > >> > >> > Correct, the UEFI spec (v2.7) says in "12.9 Graphics Output Protocol": >> > >> > PixelBltOnly This mode does not support a physical frame buffer. >> > >> > and >> > >> > PixelFormat Enumeration that defines the physical format of the >> > pixel. A value of PixelBltOnly implies that a linear >> > frame buffer is not available for this mode. >> >> -ETOOMANYLEVELSOFINDIRECTION >> Right, so that's a non-issue. >> >> Hopefully, that means other operating systems can also deal with the >> lack. >> >> > IIRC simply recognizing and accepting this enum constant was the point >> > of Alex's patch. >> >> Ah, yes, that makes sense now. >> It's a bit surprising things work without this patch, but GRUBs >> fallback seems to match anyway. > > To clarify: > Reviewed-by: Leif Lindholm Pushed, thanks.