On 10/22/12 18:52, Jeff VanDellen wrote: > I've come across the following information which seems relevant in > regards to Windows 7/2008's UEFI requirements.
(The following passages are from [1], which I've referenced in section III of [2].) > > "Display at Boot Time > For a platform that has a console device, the UEFI 2.0 specification > requires the firmware to implement the Simple Text Output Protocol. > Optionally, the firmware can also support a graphical protocol. UEFI > 2.0 defines the Graphic Output Protocol (GOP), and EFI 1.1 defines the > Universal Graphics Adapter (UGA) Protocol. Windows supports all three > protocols, but the user experience with each protocol is different. > For the best experience, if the firmware implements a graphical > protocol, Windows recommends and prefers the GOP. > Windows requires a graphical protocol to render glyphs for non-English > message resources. To do so, the firmware must support the following: > • A graphical protocol—either GOP or UGA. > • Either 1024x768 display resolution with 32-bit pixel color or > 800x600 display resolution with 24-bit pixel color. > > If the firmware does not support any of these graphics modes, Windows > still functions, but all boot display reverts to text mode and > English. > Windows 7 and Windows Server 2008 R2 require GOP to display a > high-resolution, animated image during boot. If GOP is not available, > Windows uses the video graphics array (VGA) standard to display a > lower resolution image and a simple progress indicator. For an optimal > boot experience with these versions of Windows, sealed platforms > without expansion card slots can safely boot with graphics mode > enabled and eliminate transitions to text mode. > Whenever the firmware boot manager hands off execution to a Windows > EFI application, platform firmware and the firmware boot manager must > not use the frame buffer for any purpose." The core of the problem is precisely that: *even though* the OVMF GOP supports - 800x600x32, - 1024x768x24, - and with my recent patch, 800x600x24, the windows UEFI installer (the kernel in the WinPE phase) *nonetheless* requires a VGA BIOS. Ie. not "either-or": "always". This Windows 7 / Server 2008 R2 bug is what Razvan has repeatedly pointed out on the web, and what Windows 8 / Windows Server 2012 apparently fix. The latter in fact rely on the GOP only, as they should. (... until the "real" video driver is loaded of course.) Laszlo [1] http://www.feishare.com/attachments/083_UEFIrequirements.pdf [2] http://article.gmane.org/gmane.comp.bios.tianocore.devel/799 ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel
