On Sep 21, 2016, at 5:53 PM, Benjamin Herrenschmidt wrote:

On Wed, 2016-09-21 at 14:26 -0400, G 3 wrote:

Nodes like chose, aliases, openprom are of class IOService. options
is of class IODTNVRAM. It looks like this class has problems. I'm
thinking since Alexander Graf did work in the mac_nvram.c file, he
might know what is wrong.

What is wrong is purely that MacOS X limits how you do things on that
node. Have a look at the OS X kernel source :-) The implementation of
the support libraries to run NDRVs is all there (module
IOGraphicsFamily iirc).

I will check the IOGraphicsFamily kernel extension source code.

 I found another way to access the options
node in Mac OS X. Use this command: ioreg -c IODTNVRAM. It stops at
the options node and prints this error message: "ioreg: error: can't
obtain properties" in QEMU. On a real Power Mac the command prints
all the properties of the options node just fine.

Correct, part of the problem is that I think we don't emulate the NVRAM
in a format that OS X understands, a problem for another day.

If you know any more info please share. I would like to help fix this problem.

I don't know about using binary. The way we do it now seems just fine.

ASCII parsing in a driver sucks.

All the code needed parse ASCII is already in the patch. But I will
try to see things your way.

I just need to figure out how to write to the /chosen node from the
QEMU command line. I found a function called OpenBIOS_set_var() in
openbios_firmware_abi.h, but it would require an address to write to.
So where do I find the address of the /chosen node....

No, you don't. Do as I said. Have OpenBIOS construct the list of
resolutions and put it in the node of the device itself.

That can be done, but I was hoping to be able to do this via a command-line switch. That would make things so much easier on the user. Altering properties in OpenBIOS can be challenging using forth. OpenBIOS does support using startup scripts so maybe someone could make a script that adds user resolutions to the
QEMU,VGA node from the options node.

I'm hoping you had a look at version three of my patch. If there are any other issues
with it, I would like to know before making version 4.

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