Re: Giant Locked drivers

From: Mark Millard <marklmi_at_yahoo.com>
Date: Fri, 02 Dec 2022 03:13:08 UTC
Elliott Mitchell <ehem+freebsd_at_m5p.com> wrote on
Date: Fri, 02 Dec 2022 00:33:00 UTC :

> On Tue, Nov 15, 2022 at 10:37:36AM -0700, Warner Losh wrote:
> > When set to 0, you get today's behavior. If set to 1, it will no longer
> > allow drivers that don't request MPSAFE interrupt handlers from registering
> > (the interrupt setup will return an error).
> > 
> > This will allow us to understand what is lost if we throw the switch, and
> > allow users to proactively test their systems to see if they are
> > affected or not (and if they are, if they want to live without the
> > functionality, or want to fund work in the area).
> > 
> > Comments?
> 
> . . .
> 
> 
> In other news in two handy VMs. On x86: (a full VM with hardware emulation)
> 
> atkbd0: [GIANT-LOCKED]
> psm0: [GIANT-LOCKED]
> WARNING: Device "psm" is Giant locked and may be deleted before FreeBSD 14.0.
> 
> On ARM64: (basically pure VM with no emulated hardware)
> 
> <nothing>
> 
> So right now everyone is reporting x86 console devices and nothing else.

In https://lists.freebsd.org/archives/freebsd-arch/2022-November/000290.html
I reported that RPi*'s list:

WARNING: Device "fb" is Giant locked and may be deleted before FreeBSD 14.0.

The other two types of small board computers that I have
access to do not have software support for the video.

I've no evidence beyond those tests to know if the issue is
specific to the RPi*'s vs. more general.

> This suggests the x86 console is urgent for giant removal. Then perhaps
> it will be viable to default to disabled (or perhaps something else will
> float to the top).


===
Mark Millard
marklmi at yahoo.com