From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1eCkLA-0006R1-9c for mharc-grub-devel@gnu.org; Thu, 09 Nov 2017 05:45:44 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35139) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eCkL7-0006Qo-T7 for grub-devel@gnu.org; Thu, 09 Nov 2017 05:45:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eCkL3-0003ve-Ru for grub-devel@gnu.org; Thu, 09 Nov 2017 05:45:41 -0500 Received: from serv1.kernkonzept.com ([88.99.87.17]:59171 helo=mx.kernkonzept.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eCkL3-0003uu-KN for grub-devel@gnu.org; Thu, 09 Nov 2017 05:45:37 -0500 Received: from ipb21833f8.dynamic.kabel-deutschland.de ([178.24.51.248] helo=triton) by mx.kernkonzept.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) id 1eCkIu-0004nz-G0; Thu, 09 Nov 2017 11:43:24 +0100 Date: Thu, 9 Nov 2017 11:43:17 +0100 From: Matthias Lange To: The development of GNU GRUB Cc: phcoder@gmail.com, nd@arm.com, fedora.dm0@gmail.com Subject: Re: About text mode on EFI when booting Linux Message-ID: <20171109104317.GA30899@triton> References: <20171109094950.GA19652@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171109094950.GA19652@arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 88.99.87.17 X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Nov 2017 10:45:43 -0000 Hi, On 2017-1109 at 17:49:53 +0800, Dennis Chen wrote: > Hi Vladimir, > > We encounter an error message "no suitable video mode found" when > booting a VM on i386 platform. Though I think this is not a big problem, > but the LinuxKit guys(we use grub2 in LinuxKit project) have some > concerns about this error message, so I submit a patch[1] try to > eliminate this message. Would you please take a look at that patch? > > I also dig into the commit logs of the grub2 git tree, and found below > commit: > [...] > > I am very curious about the context/background of this commit here, what's > the reason leads us not to accept a text modes on EFI when booting Linux? it appears that (U)EFI dos not feature any text services. See also this thread [1] from the help-grub mailing list. As far as I have understood things, UEFI has the "Console I/O Protocol" API which can be used to output to a console without caring about what the console actually is (serial port or something). To output something on the screen the "Graphics Output Protocol" is used which doesn't support any text mode. Best, Matthias. [1] https://lists.gnu.org/archive/html/help-grub/2011-12/msg00023.html > [1] https://lists.gnu.org/archive/html/grub-devel/2017-10/msg00031.html > > Thanks, > Dennis