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Message-ID: <bec8c0b0decc16b3533fadec8ad0f6d5c2f37d98.camel@collabora.com>
Subject: Re: [PATCH v2] media: verisilicon: Fix crash when probing encoder
From:   Nicolas Dufresne <nicolas.dufresne@collabora.com>
To:     Michael Tretter <m.tretter@pengutronix.de>,
        Linux regressions mailing list <regressions@lists.linux.dev>
Cc:     Diederik de Haas <didi.debian@cknow.org>,
        Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        p.zabel@pengutronix.de, mchehab@kernel.org,
        m.szyprowski@samsung.com, linux-media@vger.kernel.org,
        linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
        kernel@collabora.com, hverkuil-cisco@xs4all.nl,
        Pengutronix Kernel Team <kernel@pengutronix.de>
Date:   Thu, 25 May 2023 10:32:15 -0400
In-Reply-To: <20230523145430.GB9943@pengutronix.de>
References: <20230413104756.356695-1-benjamin.gaignard@collabora.com>
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         <7c1bf9c4-f14b-30cd-2610-871f5f512d06@collabora.com>
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         <5d871928-dcd5-3f27-e975-d1639525dad0@leemhuis.info>
         <20230523145430.GB9943@pengutronix.de>
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Hi Micheal,

Le mardi 23 mai 2023 =C3=A0 16:54 +0200, Michael Tretter a =C3=A9crit=C2=A0=
:
> On Tue, 23 May 2023 12:50:42 +0200, Linux regression tracking (Thorsten L=
eemhuis) wrote:
> > CCing the Regression list and a bunch of other people that were CCed in
> > threads that look related:
>=20
> Thanks!
>=20
> >=20
> > On 23.05.23 00:38, Diederik de Haas wrote:
> > > On Monday, 22 May 2023 18:17:39 CEST Benjamin Gaignard wrote:
> > > > Le 20/05/2023 =C3=A0 00:34, Diederik de Haas a =C3=A9crit :
> > > > > On Thursday, 13 April 2023 21:52:50 CEST Nicolas Dufresne wrote:
> > > [...]
> > > > > When I booted into my 6.4-rc1 (but also rc2) kernel on my
> > > > > Pine64 Quartz64 Model A, I noticed a crash which seems the same a=
s
> > > > > above, but I didn't have such a crash with my 6.3 kernel.
> > > > > Searching for 'hantro' led me to this commit as the most likely c=
ulprit
> > > > > but when I build a new 6.4-rcX kernel with this commit reverted,
> > > > > I still had this crash.
> > > > > Do you have suggestions which commit would then be the likely cul=
prit?
> > > >=20
> > > > This patch fix the crash at boot time, revert it doesn't seem to be=
 the
> > > > solution. Maybe this proposal from Marek can help you ?
> > > >=20
> > > > https://patchwork.kernel.org/project/linux-media/patch/202304211047=
59.2236463-1-m.szyprowski@samsung.com/
> > >=20
> > > That helped :) After applying that patch I no longer have the crash.
> > > Thanks!
> >=20
> > That regression fix is now a month old, but not yet merged afaics --
> > guess due to Nicolas comment that wasn't addressed yet and likely
> > requires a updated patch.
>=20
> I agree with Nicolas comment on that patch and it needs to be updated.
>=20
> >=20
> > Michael afaics a week ago posted a patch that to my *very limited
> > understanding of things* (I hope I don't confuse matters here!) seems t=
o
> > address the same problem, but slightly differently:
> > https://lore.kernel.org/all/20230516091209.3098262-1-m.tretter@pengutro=
nix.de/
>=20
> Correct, my patch addresses the same problem.

Sorry, just got really busy and missed the second fix. From a hot fix stand
point, your patch seems a lot safer. It does not go as far, and probably do=
es
not make the driver better, but considering we had such a slow response we =
need
to do something about it.

Ezequiel, will you be fine with the approach ?

>=20
> >=20
> > No reply yet.
> >=20
> > That's all a bit unfortunate, as it's not how regression fixes should b=
e
> > dealt with -- and caused multiple people headaches that could have been
> > avoided. :-/
> >=20
> > But well, things happen. But it leads to the question:
> >=20
> > How can we finally address the issue quickly now to ensure is doesn't
> > cause headaches for even more people?
> >=20
> > Marek, Michael, could you work on a patch together that we then get
> > somewhat fast-tracked to Linus to avoid him getting even more unhappy
> > about the state of things[1]?
>=20
> Marek, if you have an updated patch, I will happily test and review it.
> Otherwise, please take a look at my patch.
>=20
> Michael
>=20