NVIDIA FreeBSD kernel feature requests

Alexander Kabaev kan at kan.dnsalias.net
Thu Jun 29 16:49:12 UTC 2006

On Thu, Jun 29, 2006 at 09:32:42AM -0700, Kip Macy wrote:
> IIRC lack of per instance cdevs also limits Freebsd to one vmware instance.
>            -Kip
> On 6/29/06, Oleksandr Tymoshenko <gonzo at pbxpress.com> wrote:
> >Christian Zander wrote:
> >> Hi all,
> >>  # Task:        implement mechanism to allow character drivers to
> >>                 maintain per-open instance data (e.g. like the Linux
> >>                 kernel's 'struct file *').
> >>    Motivation:  allows per thread NVIDIA notification delivery; also
> >>                 reduces CPU overhead for notification delivery
> >>                 from the NVIDIA kernel module to the X driver and to
> >>                 OpenGL.
> >>    Priority:    should translate to improved X/OpenGL performance.
> >>    Status:      has not been started.
> >	I've stumbled across this issue a while ago. Actually it can
> >be partially solved using EVENTHANDLER_REGISTER of dev_clone event with
> >keeping state structure in si_drv1 or si_drv2 fields. I'm not sure it's
> >the best solution but it works for me though it smells like hack, and
> >looks like hack :) Anyway, having legitimate per-open instance data
> >structures of cdevs is a great assistance in porting linux drivers to
> >FreeBSD. Just my $0.02.
> >

WHY it smells like a hack? It was designed precisely to do that. I am
using cloned devices in our  product with great success. Every client
opening 'magic' device gets its own exclusive cloned device instance
and everything works like a charm. I am yet to hear any single coherent
description of what Linux's approach has over device cloning in FreeBSD.
I wouldn't mind being educated on this.

Alexander Kabaev
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