[OpenBIOS] [PATCH v2] Implement copy-resolutions-property

[Mark Cave-Ayland]

On 01/10/16 19:44, Programmingkid wrote:

> On Oct 1, 2016, at 2:11 PM, Mark Cave-Ayland wrote:
> 
>> On 26/09/16 18:05, Programmingkid wrote:
>>
>>> The copy-resolutions-property copies all the resolutions from the resolutions
>>> property of the options node to the resolutions property of the QEMU,VGA node.
>>> This is used to support specifying resolutions via the command-line.
>>>
>>> Signed-off-by: John Arbuckle <programmingkidx at gmail.com>
>>> ---
>>> v2:
>>> Eliminated all if conditions.
>>>
>>> arch/ppc/qemu/qemu.fs | 10 ++++++++++
>>> 1 file changed, 10 insertions(+)
>>>
>>> diff --git a/arch/ppc/qemu/qemu.fs b/arch/ppc/qemu/qemu.fs
>>> index 3d99a34..b53115a 100644
>>> --- a/arch/ppc/qemu/qemu.fs
>>> +++ b/arch/ppc/qemu/qemu.fs
>>> @@ -138,3 +138,13 @@ variable keyboard-phandle 0 keyboard-phandle !
>>>     3drop 0
>>>   then
>>> ;
>>> +
>>> +\ Copies the resolutions property from the /options node to QEMU,VGA node
>>> +
>>> +: copy-resolutions-property  ( -- )
>>> +    " /options" find-device
>>> +    " resolutions" active-package get-package-property
>>> +    abort" copy-resolutions-property: Failed to find resolutions property!"
>>> +    " /pci/QEMU,VGA" find-device
>>> +    " resolutions" property
>>> +;
>>
>> Some more general thoughts on the approach: I think that you're doing
>> this the wrong way around. Rather than injecting the resolutions into
>> the QEMU,VGA device, I think the better way is to alter QEMU,VGA.fs so
>> that it searches for an optional "fb-modes" property under /options,
>> parses it, and then sets its own encode-int property version.
> 
> I suppose this would only require a few changes to my patches. I just feel
> the word 'resolutions' is easier to remember and type than 'fb-modes'.
> 
> What is the advantage of doing things this way?

Well OpenBIOS has always been intended to be as close to real hardware
implementations as possible, so if there is an existing standard we
should use it.

>> Also you never replied if there was a way of reading the in-built
>> resolutions from the QEMU VGA controller? If yes, let's grab the
>> information from there. If not, then it would make sense to add the
>> basic VGA/XGA resolutions into the QEMU,VGA device as default and then
>> simply add any custom resolution to the end of the list.
> 
> I'm sorry I didn't answer your question. I must have missed it. Do you
> know what file has these built-in resolutions? Currently I do not know
> a way to access these resolutions.

You need to see if you can read this information somehow from the VGA
contoller or via VBE.

>> Finally for reference take a look at the Sun Framebuffer FAQ at
>> http://www.sunhelp.org/faq/FrameBuffer.html to check the format the mode
>> string should be in (it seems to be the format eluded to earlier by
>> Tarl) and also the parameter should perhaps be called "fb-mode" which is
>> the name used by Apple's OF implementation.
> 
> Is this the format: widthxheightxbitdepth ? I just think it is easier to
> specify only width and height. The monitors control panel in Mac OS 9 allows
> the user to switch the bitdepth at any resolution (within vram limits). 
> 
> Do you have any documentation on the fb-mode property? I did a quick check
> on my Macintosh's video card node in open firmware and couldn't find this
> fb-mode property. 

Just google, since I own no PPC Mac hardware :)


ATB,

Mark.