nanogui: More...Porting to a custom video device
Subject:
RE: [nanogui] More...Porting to a custom video device
From:
Simon Wood ####@####.####
Date:
24 May 2001 15:36:35 -0000
Message-Id: <44632C76B97BD211AF6B00805FADCAB208790652@exchange.saltaire.pace.co.uk>
> -----Original Message-----
> From: Jordan Crouse ####@####.####
> Sent: Thursday, May 24, 2001 3:59 PM
> To: Simon Wood; ####@####.####
> Subject: Re: [nanogui] More...Porting to a custom video device
>
> There are several reasons why I wouldn't do this:
[Simon Wood]
You only quoted two ;-)
> 1. Without the kernel interface, you have to resort to somewhat ticky tack
> methods of determine screen size, depth, colormap, etc, etc.. The kernel
> gives you a universal method to determine everything you need to know about
> the display.
[Simon Wood]
Yes, but at a cost of size and performance. Compare a
framebuffer verses a serial console kernel (heck who needs
a console at all??).
If you are embedding Microwindows into an appliance things
like screen dimensions and colour depth are decided at the
design stage, long before the programmers get to touch the
device.
In this case the 'scr_???.c' file would be written for that
specific device.
> 2. Any way you slice it, you will still need some sort of kernel driver to
> initalize and communicate with the hardware. (Unless of course your hardware
> can be initalized by the BIOS and access through the standard VGA memory
> window - but then if it could, why not use VESA?)
[Simon Wood]
Please don't think I'm having a go at you, but a lot of people
don't seem to appreciate that an appliance is NOT a P.C.
So, for example, a 'Fancy Git' phone may use microwindows as
it's user interface but it won't contain any P.C. like
functionality, will probably run from flash and be very simple
in comparison to normal P.C. It probably won't have any 'BIOS'.
Wrt to initilsation, this could be handled by the Microwindows
driver (scr_???.c function ???_open() ).
Please also note that I don't know exactly what Gordon has in
mind, I was just trying to point out that he may be putting a
lot more in the chain than he has too. It is obviously up to
him which technique to choose.
One of the major advantages of the way Microwindows is designed
is the amount of choice in how you adopt it, suiting it to
your hardware (and software) platform. It also gives the
portability that you can design your application on one platform
(say P.C.) and shift to the real target when the hardware comes
back from manufacture.
