On Wed, Jan 8, 2014 at 3:48 PM, Arnd Bergmann arnd@arndb.de wrote:
On Wednesday 08 January 2014, Geert Uytterhoeven wrote:
VGA is special, in that it uses "ISA memory space". This is not a subset of "PCI memory space", but something different. Some PCI host bridges (IIRC, e.g. on Mac) do not allow access to this space. Most other "PC I/O" use ISA I/O space, which is a subset of PCI I/O space.
Right, but they often go together, and I think vgacon actually requires both, doesn't it? I'm not aware of anything else requiring access to the
Yes, VGA uses both.
0xa0000-0xfffff or the 0xf00000-0xffffff ISA memory windows except VGA, but I could be missing some less common devices. These are often not available on non-x86 systems, which prevents VGA from working even if low I/O space addresses are routed to PCI.
And MDA, for mdacon.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds