Re: [PATCH] New x86_64 EFI patch

[Bean]

On Sat, Jul 12, 2008 at 11:26 PM, Robert Millan <address@hidden> wrote:
> On Sat, Jul 12, 2008 at 11:16:31PM +0800, Bean wrote:
>> On Sat, Jul 12, 2008 at 10:41 PM, Robert Millan <address@hidden> wrote:
>> > On Wed, Jul 09, 2008 at 12:31:53AM +0800, Bean wrote:
>> >> > -- I tried passing video=intelfb to linux; it worked under grub2-pc but
>> >> > didn't improve anything under efi.
>> >>
>> >> intelfb doesn't work. The only way to see console in efi is to use
>> >> video=vesafb or video=efifb.
>> >
>> > How come?  I thought intelfb used the bare hardware.
>>
>> The video register in efi mode is not setup in the same way as bios.
>> There are two sets of register. In EFI, set A is completely zero,
>> while set B have non-zero value. But in bios mode, both set have
>> non-zero value. I guess this is because bios have text and graphic
>> mode, while efi only have graphic mode. (text mode in efi is emulated)
>
> But isn't intelfb supposed to access the hardware without any support
> from bios/vesa or efi?

Intelfb uses the environment setup before, it doesn't try to
reinitialize video registers.

-- 
Bean