Re: CVS commit: src/sys/dev/wsfb

[Michael <macallan%netbsd.org@localhost>]

Hello,

On Sun, 18 Oct 2020 11:54:21 +0000
"Rin Okuyama" <rin%netbsd.org@localhost> wrote:

> Module Name:	src
> Committed By:	rin
> Date:		Sun Oct 18 11:54:21 UTC 2020
> 
> Modified Files:
> 	src/sys/dev/wsfb: genfb.c
> 
> Log Message:
> For WSDISPLAYIO_GET_FBINFO ioctl, set WSFB_VRAM_IS_RAM to fbi_flags
> when shadow FB is used.

This flag is a hint for X, telling it that the memory used as
framebuffer is regular RAM ( where using a shadowfb in X would be a
waste of time and RAM ), not for example PCI RAM ( where a shadowfb
would be faster ).
In other words, it's supposed to tell X not to shadow the framebuffer.
This is why it's not set by genfb itself, which doesn't have such
knowledge about the hardware, but by drivers which do.
Shadow fb use in wsdisplay is completely private and mapping the
framebuffer through genfb will always give you whatever genfb thinks is
the actual device framebuffer.

have fun
Michael