Re: [PATCH] Add apple_set_os command

[andreas@heider.io]

Am 2014-01-03 19:38, schrieb SevenBits:
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> On 01/03/2014 01:46 AM, Vladimir '?-coder/phcoder' Serbinenko wrote:
>> On 31.12.2013 00:11, SevenBits wrote:
>>> On Monday, December 30, 2013, Andreas Heider wrote:
>>> 
>>> The EFI on current macbooks configures hardware differently
>>> depending on wether it is booting Mac OS X or a different os, for
>>> example disabling the internal GPU completely on some models.
>>> 
>>> Mac OS X identifies itself using a custom EFI protocol.
>>> 
>>> This adds a command that fakes the os identification, making all
>>> hardware accessible.
>>> 
>>> 
>>> Just a question: I do a lot of booting Linux on MacBooks, and I
>>> frequently suffer from this issue. How do we know that this code
>>> actually works?
>> Run on a mac with this code and without and compare results. The
>> ship of "works by sane design" has long since sailed away. For
>> most manufacturers it's somewhere in Moon orbit but for apple it
>> has long since left solar system.
> So, Andreas, I tried your patch, and... no dice. The Mac behaves
> exactly as before. I'm afraid it didn't appear to do anything for me.

Hi,
thanks for testing! I suspect that your MacBook Pro is simply too old. I 
don't know exactly when this protocol was introduced, I found references 
to it on Hackintosh-Forums from a while ago and in the Mac OS X 
internals book which is also a bit older.

What effect exactly were you looking for? Your MBP doesn't have a second 
GPU to disable.
Also, AFAIK the older models disable less hardware when you boot via EFI 
than the newer ones, since Bootcamp with EFI wasn't supported.

> Furthermore, your patch didn't print any output. There wasn't any
> error message returned (i.e your "Could not locate the apple set os
> protocol." message on line 52-53). When I invoked your command from
> the GRUB normal prompt, it DID print the message however. Perhaps it
> doesn't fail if called from within a grub.cfg, or maybe it simply
> doesn't print.

If it prints something on the promt I'd say it's working as intended, 
although I'm pretty sure that I see output from it when I boot a 
grub.cfg entry.

> The Mac that I tested on was a MacBook Pro from early 2008. Clearly,
> this function isn't present on all models. I can try it on others and
> seeing if it works on them, however.

If you have the time, please do. I'd be interested in what exactly 
changes.

> Also, why the if statements on lines 59 and 65, which indicate whether
> the OS version and/or vendor was set. What is the point of them? Why
> not just call the functions directly?

It's just some output so you know that the command did something.

>> 
>> 
>> 
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