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Message-ID: <f10791773520f85857749c080af999821dd41a0d.camel@redhat.com>
Subject: Re: nouveau 0000:01:00.0: drm_WARN_ON(!found_head)
From:   Lyude Paul <lyude@redhat.com>
To:     Borislav Petkov <bp@alien8.de>, Paul Dufresne <dufresnep@zoho.com>,
        Danilo Krummrich <me@dakr.org>
Cc:     nouveau <nouveau@lists.freedesktop.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Ben Skeggs <bskeggs@redhat.com>,
        Daniel Vetter <daniel@ffwll.ch>
Date:   Wed, 13 Dec 2023 18:48:22 -0500
In-Reply-To: <114bf9f5790f637a6cdec4957244192d3bd76a04.camel@redhat.com>
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Organization: Red Hat Inc.
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Hopefully you're still on at this point - if you are, could you try startin=
g
the machine up with the following kernel module arguments passed to nouveau=
?

debug=3Ddisp=3Dtrace

Then see if you can find any lines that mention INHERIT? I have a feeling I=
'm
just going to have to add a workaround for the time being, but I'd really l=
ove
to know how we're managing to get that far on a hardware generation we neve=
r
implemented that nvkm ioctl for=E2=80=A6

On Wed, 2023-12-13 at 18:37 -0500, Lyude Paul wrote:
> agh - thank you for repeatedly poking on this, I've been busy enough with=
 GSP
> work I totally missed this. Yes - I'm quite surprised that this is blowin=
g up,
> but considering that looks to be a GT218 I guess display state readback m=
ust
> just work a bit differently there since that's really early on into the N=
V50
> days.
>=20
> The reason that was a drm_WARN_ON() was because it indicates that we're n=
ot
> reading back OR -> head assignments properly. But, I'm confused how we're=
 even
> getting that far on a non-GSP platform. I'm going to dig into this now, b=
ut if
> I don't figure out a good fix by the end of the day I'll just send a patc=
h to
> silent the warning.
>=20
> Thanks again for bugging me about this!
>=20
> On Wed, 2023-12-13 at 13:49 +0100, Borislav Petkov wrote:
> > On Wed, Dec 13, 2023 at 12:39:36PM +0100, Borislav Petkov wrote:
> > > We're getting close to releasing so I guess we either debug this or s=
hut
> > > up the WARN.
> >=20
> > Not only that - panic_on_warn turns this into an explosion so you don't
> > want that in a released kernel.
> >=20
>=20

--=20
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat