Date: Tue, 15 Nov 2022 09:52:24 -0800 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Warner Losh <imp@bsdimp.com> Cc: "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: Giant Locked drivers Message-ID: <Y3PR2GXR42LcdbDd@troutmask.apl.washington.edu> In-Reply-To: <CANCZdfrfNzb1O91T4ivMXPsUGu7mYX80pJxvQu07oe2AF=YXCw@mail.gmail.com> References: <CANCZdfrfNzb1O91T4ivMXPsUGu7mYX80pJxvQu07oe2AF=YXCw@mail.gmail.com>
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On Tue, Nov 15, 2022 at 10:37:36AM -0700, Warner Losh wrote: > > It's no secret fiant-locked drivers' days are numbered. We've been more > sluggish about eliminating Giant than had been hoped. I plan in the coming > weeks to add a tunable 'debug.giant_drivers' which initially will be set to > enable/disable giant-locked drivers in the tree. > > 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? > Is there a list of effected drivers? Grepping /var/run/dmesg.boot on my system shows only "atkbd0: [GIANT-LOCKED]". A scan of atkbd(4) shows This driver is required for the console driver syscons(4) or vt(4). So, setting debug.giant_drivers=1 will brick all FreeBSD workstations? -- Steve
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