From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x230.google.com (mail-wm0-x230.google.com [IPv6:2a00:1450:400c:c09::230]) (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 6A06B21E47D5B for ; Wed, 23 Aug 2017 07:58:32 -0700 (PDT) Received: by mail-wm0-x230.google.com with SMTP id x128so701781wmg.1 for ; Wed, 23 Aug 2017 08:01:06 -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=MKgpspiZho+3Fdkb1xwM+H6DKDmHFGmw/z2TLqmVNHA=; b=bYzMYnqBUD++vFQv0c3pMlbuGAD8aSweV94lhexOOXmt5L1rYGomZ3hXI00wAJTbYr UJFREh0Wj73AZIyYd4hqv0NK2f/p2R3pULBe9mO6Cf8LRi0f3iAfz1Uplo7WIlIt9BBd 7SFuROjnsKNvwSBLzTHjuvTVME9I+FlDP2oGg= 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=MKgpspiZho+3Fdkb1xwM+H6DKDmHFGmw/z2TLqmVNHA=; b=E07p32QQvU6bsQcQe23337I2on9MHRcL8Ew9EXij4IFKpICnrBwyocJpIvc8dQllLf qUS8zdkdrgeDWzVqrCTUDu54DbyBIxW+E8NLh2pc7Z3Vi7r4om5rp4VTTwHq4/eDTAXN FjMEfMvBH3+s+7X8fNPI780WYloO5iLJE8rI1fHh9NRLD2TRnMmPOc1ODMYSnYu8iw5d yIBeTq2jONkejaC9kcwL0eFzqX10W8TNx2+k0N8Jtkgt6Fa8uX4BauTUxmXCo/63ASkj kFGdtB5q1rqZMtiXc9tVK9zurPlMdcvMcfNqFlSk4CbptHxqxBFqVa/vlVoKIByE/tXQ UEyA== X-Gm-Message-State: AHYfb5j2rIkoLRICzOneYO/mFpVvNTzfB9ObiXOEPGfNlGfSFeXY/6Kt Hv08qZR3v3Blnq1s X-Received: by 10.28.17.73 with SMTP id 70mr1871883wmr.44.1503500461503; Wed, 23 Aug 2017 08:01:01 -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 o71sm2784603wmg.15.2017.08.23.08.00.59 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 23 Aug 2017 08:01:00 -0700 (PDT) Date: Wed, 23 Aug 2017 16:00:57 +0100 From: Leif Lindholm To: Laszlo Ersek Cc: Ard Biesheuvel , "edk2-devel@lists.01.org" , Jordan Justen Message-ID: <20170823150057.mddgzpucjtbg3u3o@bivouac.eciton.net> References: <20170822163013.12233-1-ard.biesheuvel@linaro.org> <20170823131516.6f4d2p6jy222ch6m@bivouac.eciton.net> <97d8b88a-9583-2a53-7061-33e0351d622b@redhat.com> MIME-Version: 1.0 In-Reply-To: <97d8b88a-9583-2a53-7061-33e0351d622b@redhat.com> 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: Wed, 23 Aug 2017 14:58:32 -0000 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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. / Leif