FAILED: patch "[PATCH] media: ipu-bridge: do not use the CVS device lookup for IVSC" failed to apply to 7.3-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 7.3-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-7.3.y
git checkout FETCH_HEAD
git cherry-pick -x ce92674d8d8b29562de397b437e16bee499dd92b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107050253-failed-7.3-ce92674d8d8b@kernel.org' --subject-prefix 'PATCH 7.3.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From ce92674d8d8b29562de397b437e16bee499dd92b Mon Sep 17 00:00:00 2001
From: Sergey Zagursky <gvozdoder@gmail.com>
Date: Wed, 2 Sep 2026 22:15:24 +0100
Subject: [PATCH] media: ipu-bridge: do not use the CVS device lookup for IVSC

Since commit c6b1b34b5090 ("media: pci: intel: Add CVS support for IPU
bridge driver") the internal camera no longer works on laptops where the
sensor sits behind an IVSC, for example a Dell XPS 16 9640 (IPU6,
INTC10CF, ov02c10):

  intel-ipu6 0000:00:05.0: Found supported sensor OVTI02C1:00
  intel-ipu6 0000:00:05.0: Connected 1 cameras
  ivsc_csi intel_vsc-92335fcf-3203-4472-af93-7b4453ac29da: mei-csi probed
      without device fwnode!

No sensor subdevice is registered, the media graph has no sensor entity
and userspace finds no camera at all.

ipu_bridge_get_ivsc_csi_dev() first looks for the platform device named
"intel_vsc" and returns its mei-csi child. That device is created by
mei_vsc, which on this machine only appears once the LJCA USB bridge and
its SPI controller have probed, about a second after the IPU6 probe that
runs the bridge:

  07:59:29.297  platform INTC10CF:00 created (ACPI scan)
  07:59:41      intel-ipu6 probe -> ipu_bridge_init()
  07:59:42.391  platform intel_vsc created (mei_vsc)

The commit above added two fallbacks for CVS which match on the ACPI
companion alone. They are reached for every entry of ivsc_acpi_ids[],
IVSC IDs included. The IVSC ACPI device has two physical nodes:

  INTC10CF:00/physical_node  -> platform/INTC10CF:00  (no driver bound)
  INTC10CF:00/physical_node1 -> platform/intel_vsc    (mei_vsc)

so bus_find_device_by_acpi_dev(&platform_bus_type, adev) returns the bare
platform device. ipu_bridge_instantiate_ivsc() then attaches the IVSC
software node to that device instead of to the mei-csi client, the bridge
reports success, and the probe is never retried. mei_csi later probes
without a fwnode, the CSI-2 link is never described, and the sensor ACPI
device, which has an honoured _DEP on the IVSC device, is never
enumerated.

Before those fallbacks existed the lookup returned NULL here, the bridge
failed with -ENODEV and the probe was retried once the IVSC device had
shown up.

Skip those fallbacks for IVSC devices, keying on the IVSC IDs rather than
the CVS ones: new CVS IDs keep being added, whereas the IVSC list is
complete. CVS binds a driver to the ACPI device itself, so matching on the
companion stays unambiguous there.

Fixes: c6b1b34b5090 ("media: pci: intel: Add CVS support for IPU bridge driver")
Link: https://lore.kernel.org/linux-media/20260901194526.6369-1-gvozdoder@gmail.com/
Cc: stable@vger.kernel.org
Assisted-by: Claude Code:claude-opus-5
Signed-off-by: Sergey Zagursky <gvozdoder@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/pci/intel/ipu-bridge.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/media/pci/intel/ipu-bridge.c b/drivers/media/pci/intel/ipu-bridge.c
index 125fe5da7a60a..883a90249602f 100644
--- a/drivers/media/pci/intel/ipu-bridge.c
+++ b/drivers/media/pci/intel/ipu-bridge.c
@@ -232,6 +232,19 @@ static const struct acpi_device_id ivsc_acpi_ids[] = {
 	{ "INTC10FA" }, /* NVL */
 };
 
+/*
+ * The subset of ivsc_acpi_ids[] which are IVSC, rather than CVS, devices. The
+ * CVS IDs are deliberately not listed here: new ones keep being added, whereas
+ * this list is complete.
+ */
+static const struct acpi_device_id ivsc_only_acpi_ids[] = {
+	{ "INTC1059" },
+	{ "INTC1095" },
+	{ "INTC100A" },
+	{ "INTC10CF" },
+	{ }
+};
+
 static struct acpi_device *ipu_bridge_get_ivsc_acpi_dev(struct acpi_device *adev)
 {
 	unsigned int i;
@@ -283,6 +296,17 @@ static struct device *ipu_bridge_get_ivsc_csi_dev(struct acpi_device *adev)
 		return csi_dev;
 	}
 
+	/*
+	 * The lookups below match on the ACPI companion alone. That is fine for
+	 * CVS, which binds a driver to that very device, but not for IVSC: there
+	 * the ACPI device also has a driverless platform device, which would be
+	 * returned instead of the mei-csi client. Return NULL for IVSC so that
+	 * the caller fails and the probe is retried once the IVSC device shows
+	 * up.
+	 */
+	if (!acpi_match_device_ids(adev, ivsc_only_acpi_ids))
+		return NULL;
+
 	/* Try to locate CVS device on the I2C bus */
 	csi_dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
 	if (csi_dev)
-- 
2.53.0