Re: [PATCH] fbdev: suppress warning when assigning vga-save/restore base

On 08/05/2013 02:02 PM, H. Peter Anvin wrote:

On 08/05/2013 01:29 PM, Ondrej Zajicek wrote:

quoted

How this could even work? AFAIK these cards have to be explicitly programmed
to enable MMIO (which was not done in the patches). These patches claim that
it is for multi-domain PCI. I would guess that vgabase is NULL in common
configurations but if it is non-NULL, it probably wouldn't work, unless
there is some hardware magic that transparently converts MMIO (from CPU PoV)
to port IO (from card/PCI PoV).

They presumably use iowrite/ioread, which use either I/O instructions or
memory instructions depending on the address.

So the confusion really is in the iowrite interface, which can take
either a physical port address or a virtual memory address...

	-hpa