[MinnowBoard] 64-bit vs 32-bit UEFI - What you need to know!

selsinork at gmail.com selsinork at gmail.com
Sun Sep 14 09:51:30 UTC 2014


What X does today really isn't the point, X should be using KMS today, not any sort of emulation and besides, X isn't the only thing that uses this.

The point is that you can't make the need for something like this go away, and it's not supported on x86_64. Therefore there's still a need for a 32bit kernel in certain circumstances.

We'd probably all like to just move to 64bit and ditch all the legacy baggage. Reality tends to get in the way of what we'd like that as the requirement for different flash programs on different uefi versions shows :)

On 12/09/14 20:53, Adam Goode wrote:
> X doesn't use this support. It has an x86 emulator that it uses on all
> platforms these days.
>
> On Fri, Sep 12, 2014 at 3:49 PM,  <selsinork at gmail.com> wrote:
>> On 12/09/14 18:10, "Thomas B. Rücker" wrote:
>>
>> You can run either a multi-arch distro or a 32-bit userland with a 64bit
>> kernel.
>> Unless you need to somehow plug some binary only 32bit kernel module in,
>> there should be no reason for a 32bit kernel, from what I can tell.
>>
>>
>> config VM86
>>         bool "Enable VM86 support" if EXPERT
>>         default y
>>         depends on X86_32
>>         ---help---
>>           This option is required by programs like DOSEMU to run
>>           16-bit real mode legacy code on x86 processors. It also may
>>           be needed by software like XFree86 to initialize some video
>>           cards via BIOS. Disabling this option saves about 6K.
>>
>> It had been a while since I'd looked, so wasn't sure if this was still the
>> case after the X86 restructuring, but seems that it still requires a 32 bit
>> kernel to work.
>>
>> This isn't for any binary-only stuff or kernel modules, it's standard
>> userspace code.  Sometimes there are alternatives, sometimes not. What it's
>> referring to with the XFree86 comment is the need to run some code from rom
>> on an add-in card. Legacy reasons mean this is typically 16bit code.  PC's
>> have the advantage of being quite standardised and very backward compatible,
>> but that does come with baggage like needing to be compatible with 1981.
>>
>>
>>
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