Re: [PATCH 06/12] macfb: implement mode sense to allow display type to be detected

[Laurent Vivier]

Le 04/10/2021 à 12:32, BALATON Zoltan a écrit :
> On Mon, 4 Oct 2021, Laurent Vivier wrote:
>> Le 02/10/2021 à 13:00, Mark Cave-Ayland a écrit :
>>> The MacOS toolbox ROM uses the monitor sense to detect the display type and 
>>> then
>>> offer a fixed set of resolutions and colour depths accordingly. Implement 
>>> the
>>> monitor sense using information found in Apple Technical Note HW26: 
>>> "Macintosh
>>> Quadra Built-In Video" along with some local experiments.
>>>
>>> Since the default configuration is 640 x 480 with 8-bit colour then hardcode
>>> the sense register to return MACFB_DISPLAY_VGA for now.
>>>
>>> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
>>> ---
>>>  hw/display/macfb.c         | 117 ++++++++++++++++++++++++++++++++++++-
>>>  hw/display/trace-events    |   2 +
>>>  include/hw/display/macfb.h |  20 +++++++
>>>  3 files changed, 137 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/hw/display/macfb.c b/hw/display/macfb.c
>>> index 62c2727a5b..5c95aa4a11 100644
>>> --- a/hw/display/macfb.c
>>> +++ b/hw/display/macfb.c
>>> @@ -28,8 +28,66 @@
>>>  #define MACFB_PAGE_SIZE 4096
>>>  #define MACFB_VRAM_SIZE (4 * MiB)
>>>
>>> -#define DAFB_RESET      0x200
>>> -#define DAFB_LUT        0x213
>>> +#define DAFB_MODE_SENSE     0x1c
>>> +#define DAFB_RESET          0x200
>>> +#define DAFB_LUT            0x213
>>> +
>>> +
>>> +/*
>>> + * Quadra sense codes taken from Apple Technical Note HW26:
>>> + * "Macintosh Quadra Built-In Video". The sense codes and
>>
>> https://developer.apple.com/library/archive/technotes/hw/hw_26.html
> 
> URLs may change or go away so I think it's better to reference by title in 
> comments, then one can
> find it by that whereas a stale URL is not much help a few years from now.

This URL is very stable (hosted by Apple for 30 years now...) and providing it 
could help to find a
copy of the document in an internet archive. I had some difficulties to find it 
using the title or
the TN number.

Thanks,
Laurent