Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:5 as permitted sender) client-ip=2620:137:e000::3:5;
Message-ID: <114bf9f5790f637a6cdec4957244192d3bd76a04.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 18:37:22 -0500
In-Reply-To: <20231213124936.GCZXmoYDq8nMRs75XM@fat_crate.local>
References: <20231111120323.GAZU9tiw8e0RSzCGB9@fat_crate.local>
         <20231212224037.GAZXjhZUDeoq50xKJ5@fat_crate.local>
         <18c613ec092.ae61cf7d6029.4389632938517239705@zoho.com>
         <20231213113936.GBZXmX+MKqX/qOnPn1@fat_crate.local>
         <20231213124936.GCZXmoYDq8nMRs75XM@fat_crate.local>
Organization: Red Hat Inc.
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) 
MIME-Version: 1.0
Precedence: bulk

agh - thank you for repeatedly poking on this, I've been busy enough with G=
SP
work I totally missed this. Yes - I'm quite surprised that this is blowing =
up,
but considering that looks to be a GT218 I guess display state readback mus=
t
just work a bit differently there since that's really early on into the NV5=
0
days.

The reason that was a drm_WARN_ON() was because it indicates that we're not
reading back OR -> head assignments properly. But, I'm confused how we're e=
ven
getting that far on a non-GSP platform. I'm going to dig into this now, but=
 if
I don't figure out a good fix by the end of the day I'll just send a patch =
to
silent the warning.

Thanks again for bugging me about this!

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 shu=
t
> > 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
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat