From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-x235.google.com (mail-wr0-x235.google.com [IPv6:2a00:1450:400c:c0c::235]) (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 275B921E47D55 for ; Thu, 24 Aug 2017 04:59:57 -0700 (PDT) Received: by mail-wr0-x235.google.com with SMTP id w9so1629116wre.1 for ; Thu, 24 Aug 2017 05:02:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=1s9R2dUZE0ZWYoYB8fSEagHRsV4PekzlTXYD7bHaMNc=; b=aV3Ra8FqoPVNy0NQyFyItQqSiAzG/IKPl7dv7nzWkW6AeMvfUpCO/93mjDVOtAdGYX YblmVcBqtEsF5S1gSG/iM9yvroFYRoY7QbonhvIGlvRqHIQ84SLaQDygf5ie+4YoeJCg bb8sdoyKT4HFwusquYodmYDtsdLYoHlOm1cBI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=1s9R2dUZE0ZWYoYB8fSEagHRsV4PekzlTXYD7bHaMNc=; b=kuqfGyyZODy/fOTeWo3FAjBgTPIIyvWEj/YcjmlkKOU9ONQ/N1hlwnufrXsGS69QJ7 /L0OQGSuR+x0Q6MUn3GJaMVnrLGn6D9yZhX2oIkSADws56AmsEwEQUZXMbsNJskfyeia ec1JHzWZJcGgtbMgW4e4AeB0YI4VxsxpgtJ5hLhVDhTaee8RsGXTaonjKYIwa6hu0cqH kp8p62Ev38UFHJhcQgs8xkLuLMhKdWxO5t5j/9D20ItReKsN+EXZRENy5B2yfwfG/giZ VsM/raNtcUn1hNOjKe5/WFGLyiPqvpeSWheqBA07aUq+wwgJtJ+6gv/YFt4oM1FOfiIW pWKg== X-Gm-Message-State: AHYfb5hHyghFISz1AilJ4VH4CilZINoT63PRbgAnK3n6uY5NnbPhh76a 4JzdOa8oEu92ekVi X-Received: by 10.223.141.212 with SMTP id o78mr4467316wrb.215.1503576150651; Thu, 24 Aug 2017 05:02:30 -0700 (PDT) Received: from bivouac.eciton.net (bivouac.eciton.net. [2a00:1098:0:86:1000:23:0:2]) by smtp.gmail.com with ESMTPSA id 73sm4308920wmo.1.2017.08.24.05.02.28 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 24 Aug 2017 05:02:29 -0700 (PDT) Date: Thu, 24 Aug 2017 13:02:26 +0100 From: Leif Lindholm To: Laszlo Ersek Cc: Ard Biesheuvel , "edk2-devel@lists.01.org" , Jordan Justen Message-ID: <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> MIME-Version: 1.0 In-Reply-To: <20170823150057.mddgzpucjtbg3u3o@bivouac.eciton.net> User-Agent: NeoMutt/20170113 (1.7.2) 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 11:59:57 -0000 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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