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From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: Wed, 12 Jun 2024 14:32:26 +0200
Message-ID: <CAJZ5v0hOBggQR_=uA3VuhruQnZihVxHHovpTz4=qfcbiSunsYw@mail.gmail.com>
Subject: Re: [PATCH 1/1] ACPI: scan: Ignore Dell XPS 9320 camera graph port nodes
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>, Hans de Goede <hdegoede@redhat.com>, 
	Genes Lists <lists@sapience.com>, linux-kernel@vger.kernel.org, mchehab@kernel.org, 
	hverkuil-cisco@xs4all.nl, laurent.pinchart@ideasonboard.com, 
	wentong.wu@intel.com, linux-media@vger.kernel.org, linux-acpi@vger.kernel.org, 
	"regressions@lists.linux.dev" <regressions@lists.linux.dev>
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Hi Sakari,

On Wed, Jun 12, 2024 at 2:26=E2=80=AFPM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> Hi Rafael,
>
> On Wed, Jun 12, 2024 at 02:21:51PM +0200, Rafael J. Wysocki wrote:
> > On Wed, Jun 12, 2024 at 2:10=E2=80=AFPM Sakari Ailus
> > <sakari.ailus@linux.intel.com> wrote:
> > >
> > > Hi Hans,
> > >
> > > Just read this discussion, too...
> > >
> > > On Wed, Jun 12, 2024 at 12:08:49PM +0200, Hans de Goede wrote:
> > > > Hi,
> > > >
> > > > On 6/6/24 8:12 PM, Hans de Goede wrote:
> > > > > Hi,
> > > > >
> > > > > +To: Rafael since this was Cc-ed to linux-acpi but never send
> > > > > to Rafael directly.
> > > > >
> > > > > Rafael this fixes a crash in 6.10-rc1 for some users and is neces=
sary
> > > > > to make the cameras work on the Dell XPS 13 plus 9320 .
> > > > >
> > > > > On 5/28/24 7:09 PM, Hans de Goede wrote:
> > > > >> Hi Sakari,
> > > > >>
> > > > >> On 5/28/24 10:44 AM, Sakari Ailus wrote:
> > > > >>> Ignore camera related graph port nodes on Dell XPS 9320. They d=
ata in BIOS
> > > > >>> is buggy, just like it is for Dell XPS 9315. The corresponding =
software
> > > > >>> nodes are created by the ipu-bridge.
> > > > >>>
> > > > >>> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > >>> ---
> > > > >>> Hi,
> > > > >>>
> > > > >>> Could you test this and see whether it fixes the warning?
> > > > >>>
> > > > >>> The camera might work with this change, too.
> > > > >>
> > > > >> Thank you I just received a Dell XPS 13 plus 9320 myself to use
> > > > >> for VSC testing and I can confirm that with this patch 6.10.0-rc=
1
> > > > >> works, including giving a picture with the libcamera software IS=
P +
> > > > >> 3 small libcamera patches.
> > > > >
> > > > > I forgot to add:
> > > > >
> > > > > Tested-by: Hans de Goede <hdegoede@redhat.com>
> > > > > Reviewed-by: Hans de Goede <hdegoede@redhat.com>
> > > >
> > > > I just hit the same problem on another Dell laptop. It seems that
> > > > all Dell laptops with IPU6 camera from the Tiger Lake, Alder Lake
> > > > and Raptor Lake generations suffer from this problem.
> > > >
> > > > So instead of playing whack a mole with DMI matches we should
> > > > simply disable ACPI MIPI DISCO support on all Dell laptops
> > > > with those CPUs. I'm preparing a fix for this to replace
> > > > the DMI matching now.
> > >
> > > DisCo for Imaging support shouldn't be dropped on these systems, and =
this
> > > isn't what your patch does either. Instead the ACPI graph port nodes =
(as
> > > per Linux specific definitions) are simply dropped, i.e. this isn't r=
elated
> > > to DisCo for Imaging at all.
> >
> > So it looks like the changelog of that patch could be improved, right?
>
> Well, yes. The reason the function is in the file is that nearly all came=
ra
> related parsing is located there, not that it would be related to DisCo f=
or
> Imaging as such.

So IIUC the camera graph port nodes are created by default with the
help of the firmware-supplied information, but if that is defective a
quirk can be added to skip the creation of those ports in which case
they will be created elsewhere.

Is this correct?