[Bug 2092139] [NEW] Rename media device as ipu6-downstream in Noble

[Launchpad Bug Tracker]

You have been subscribed to a public bug by You-Sheng Yang (vicamo):

[SRU Justificaiton]

[ Impact ]

Latest IPU6/7 userspace framework becomes incompatible with ipu6-drivers
using out-of-tree ipu6-isys kernel module.

1. The userspace framework has to be compatible with all kernels, and
therefore all ipu6 kernel driver revisions, available in Noble.

2. There are implementation differences between the upstreamed ipu6-isys
driver and that from out-of-tree git repository. Such differences are
identified by a media device model name.

3. The out-of-tree driver ipu6-isys used to identify itself as "ipu6",
but while it being upstreamed, this formal name was taken to identify
the in-tree ipu6-isys driver, and therefore demanding the out-of-tree
one to be renamed as "ipu6-downstream" instead.

4. The latest userspace framework has adopted such naming policy, so all
the kernels that are still using out-of-tree ipu6-isys with such name
identity must take corresponding action so that it won't be
misidentified by the framework.

[ Test Plan ]

1. install kernel from -proposed pocket.

2. install necessary (ipu6/ipu7/usbio/vision) linux-modules-
FOO-<variant> corresponding packages for the kernel.

3. For kernels > v6.10 it should be using the in-tree ipu6-isys, and out-of-tree one for kernel < v6.10. From `v4l2-ctl` output:
```
# kernel >= v6.10
$ v4l2-ctl -D -d 1
Driver Info:
        Driver name: intel-ipu6-isys
        Card type  : ipu6

# kernel > v6.10
$ v4l2-ctl -D -d 1
Driver Info:
        Driver name: intel-ipu6-isys
        Card type  : ipu6-downstream
```

4. Use https://webcamtests.com/ to verify camera availability.

[ Where problems could occur ]

For old userspace framework, there is no such identity checks, so the
new identity for the out-of-tree driver doesn't have an effect for the
existing setups.

[ Other Info ]

This is already part of the drivers for kernel >= v6.10, and therefore
it affects only ipu6-drivers/noble.

========== original bug report ==========

The Intel's ARL enablement release (bug 2085845) also makes use of in-
tree IPU6 ISYS kernel modules for kernel versions >= 6.10. This is not
optional, and the differences between the in-tree and out-of-tree isys
kernel modules result in the need of the compatibility handling only
available in userspace HAL >= 20241122. The new kernel driver depends on
the new HAL.

To be worse, the media device model name that used to be "ipu6" is
chosen to serve as an identity to distinguish the upstream (in-tree) and
downstream (out-of-tree) implementation of isys. While the upstreamed
isys driver must use "ipu6" as the model name, it means the downstream
one has to rename media device model as "ipu6-downstream". Since the old
ipu6-drivers always use "ipu6", and the new HAL assumes "ipu" means the
in-tree isys but it's not, all the old ipu6-drivers deployments has to
rename their media device model to "ipu6-downstream" when using the new
HAL.

Then, the last problem, Noble has both oem-6.11 and oem-6.8, which
follows the oem-6.11 will need the new HAL, and the new HAL demands
intel-isys module built along with oem-6.8 to be renamed as
"ipu6-downstream".

Proposed fix: https://github.com/intel/ipu6-drivers/pull/310

** Affects: ipu6-drivers (Ubuntu)
     Importance: Undecided
         Status: Invalid

** Affects: ipu6-drivers (Ubuntu Noble)
     Importance: High
     Assignee: You-Sheng Yang (vicamo)
         Status: In Progress

-- 
Rename media device as ipu6-downstream in Noble
https://bugs.launchpad.net/bugs/2092139
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