Hi Andrew, On Fri, Jan 4, 2013 at 4:23 PM, Andrew Goodbody <[email protected]>wrote:
> On 02/01/13 19:28, David Hubbard wrote: > >> Andrew, Ron, what's your take on >> http://mjg59.dreamwidth.org/**20916.html<http://mjg59.dreamwidth.org/20916.html>? >> >> Specifically: >> "This is part of Windows 8's fast boot support - the keyboard may not be >> initialised until after the OS has started." >> > > OK, the feature is deferred initialisation of USB devices until they are > actually needed. > Windows 8 is making use of this but it is introduced as part of the UEFI > spec 2.3.1c. > This is optional to implement it or not, OEM gets to decide. > This is in the UEFI spec and can be used by other OSes than Windows eg > Grub could use it to speed up loading of Linux. > I understand. > > 4. User is thus *forced* to use Win8's "hold down shift and restart" >> feature -- adding another barrier before a user can boot her own OS. >> >> I think the biggest problem here is that the entire BIOS is made >> inaccessible, and only if Windows gives permission can you change that. >> > > Well yes and no. > 1) PS/2 keyboards are not affected, they are still initialised and > available as normal. Many laptop keyboards are implemented as PS/2 devices. > At least AMI BIOS also skips initializing PS/2 keyboards and mice. > 2) There are a number of ways that you can get USB enumerated and > keyboards initialised. > a) If HDD is not primary boot target > b) If primary boot target fails > c) If bootloader invokes EFI_SIMPLE_TEXT_INPUT_EX_**PROTOCOL. > ReadKeyStrokeEx() > > So yes, on a motherboard that implements it, with no PS/2 keyboard, with > the HDD as primary boot target and with Win8 installed then you may have to > use the Win8 menu to restart into the UEFI settings screens. And yes this > can be a small barrier to booting using an alternative method for any > reason, not just installing an alternative OS. But quite frankly I have > seen some bizarre setup screens on legacy BIOS that made choosing to boot > from a USB device an exercise in frustration. So this extra step in the > road to booting an alternate OS is not that big a deal. It can at least be > documented and is not a hard thing to do at all. Even without this there > are some machines that boot so fast it is not easy to press the key to get > to the setup screens at the right time, this may actually give a more > reliable way to get to the setup screens on those machines. > Good point - it could be a more reliable way to be sure the setup screen comes up. > > BTW 1) when you use BIOS above, you actually mean Setup. Setup is an > application launched by the BIOS to view or change system settings. The > BIOS is not accessible nor inaccessible, it is running as soon as the CPU > begins to execute code and will complete its tasks as normal according to > those system settings. > BTW 2) its UEFI firmware, not BIOS. Just as coreboot is not BIOS. > Ok, fine. David
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