Date: Thu, 28 Jan 2021 00:35:03 -0600 From: Scott Bennett <bennett@sdf.org> To: roberthuff@rcn.com Cc: freebsd-x11@freebsd.org Subject: Re: loading drm crashes system Message-ID: <202101280635.10S6Z3hl014235@sdf.org> In-Reply-To: <24592.4752.944930.118483@jerusalem.litteratus.org> References: <24590.137.690675.515036@jerusalem.litteratus.org> <68acb1a8-fcf8-a065-70d5-061669e2f70b@daemonic.se> <24591.35500.33066.12845@jerusalem.litteratus.org> <20210126070211.GB43439@FreeBSD.org> <24592.4752.944930.118483@jerusalem.litteratus.org>
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Robert Huff <roberthuff@rcn.com> wrote:
> > > Niclas Zeising asks:
> > > > When did it stop working?
> > >
> > > September ... I _think_.
> >
> > Yeah, that sounds about right.
> >
> > There are known issues with Radeon cards, they were quite well
> > supported a year ago, then something got broken. I've promised to
> > bisect this and find the cause, but there were several syscall-related
> > changes in -CURRENT though the course of the last year, so bisecting
> > just the kernel is not enough (machine won't get to login prompt if
> > the userland does not match), which cripples the process.
> >
> > I still intend to take this quest, just not sure when. :(
>
> Expanding on "September ... I think":
> Try September 26 as a reference date. Sometime close to then I
> a) updated world+kernel to the latest version of current, so also b)
> updated to the latest drm-current-kmod and gpu-firmware.
> Question: is there a way for the less sophisticated user <waves>
> to tell whether the cause is in the drm knod or the firmware kmod?
>
It may well be in both. See PR #247441, in which the firmware hangs the
GPU, the drm kmod then notices that the GPU has stopped responding, waits 10+ s,
then branches into the BIOS reset routine. Both the hang and the drm kmod
response are bugs.
Scott Bennett, Comm. ASMELG, CFIAG
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