Modernizing the OpenBSD Console

Post by JdeBP » Fri, Sep 04, 2020, 6:43 PM UTC

formerly_proven wrote: post #35

JdeBP wrote: post #26

Earlier quoted context omitted.

The "I" in "ITU" does not stand for "ANSI". (-: * https://itu.int/rec/T-REC-T.416 As M. Kochkov will attest, supporting 24-bit RGB (or even 32-bit ARGB) colour involves (a) recognizing and processing the new (sic!) control sequences from the 1990s, and (b) actually supporting having the display hardware in a non-palettized true colour mode (as opposed to using a 256-colour palettized mode and pretending). The definit…

I expect none of this (text mode, indexed colors, 16 bpp, hardware GDI/2D etc.) actually exists in hardware any more. I expect GPUs emulate all of this through shaders baked into the VBIOS/driver.

I doubt that very much. I cannot see people successfully making a business case to spend development time and money re-implementing MDA/CGA/EGA/VGA text mode, with the concomitant on-going support costs when inevitably the re-implementation misses stuff, for pretty much zero additional revenue. No, this wouldn't be implementable through drivers. It has to work during POST and IPL.

Post by JdeBP » Fri, Sep 04, 2020, 6:45 PM UTC

mjg59 wrote: post #33

JdeBP wrote: post #31

Earlier quoted context omitted.

Hah! I've been doing too much load-time stuff, obviously. (-: But if one is looking at PCI device IDs, then one is already at the level of the code having detailed knowledge of the specific hardware (even if only via some "miniport"-like system) and the point stands.

Oh, you can look at the device that the GOP instance is bound to and get the PCI device from there. At that point you just walk the BARs looking for one that's mapped in a region that covers the framebuffer address that GOP gives you. This doesn't require you to know anything about the device in question, and most of the time you'd probably get lucky by throwing glyphs in space that exists outside the framebuffer and…

The code will still have to know about blitter hardware, as I said.

Any design that depends from "you'd probably get lucky" is not a wise one. (-:

Re: Modernizing the OpenBSD Console

Re: Modernizing the OpenBSD Console