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

[Rin Okuyama <rokuyama.rk%gmail.com@localhost>]

Hi,

On 2020/10/21 15:42, Michael wrote:
> 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.

Thank you for detailed explanation!

I already reverted this commit as jmcneill@ advised me:
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/dev/wsfb/genfb.c#rev1.77

Thanks,
rin