ACK/Cmnt: [PULL v7][SRU][Jammy] Support Intel IPU6 MIPI camera on Alder Lake platforms

[Andrea Righi]

On Wed, May 25, 2022 at 06:38:44PM +0800, You-Sheng Yang wrote:
> BugLink: https://bugs.launchpad.net/bugs/1955383
> 
> [Impact]
> 
> To support Intel IPU6 MIPI camera on Alder Lake platforms.
> 
> [Fix]
> 
> Initial support for Intel IPU6 MIPI camera on Tiger Lake platforms has
> been addressed by bug 1921345 and 1939539. They are backported from
> https://github.com/intel/ipu6-drivers.
> 
> Further works to enable IPU6 camera on Alder Lake platforms depend on a
> few more fixes from same ipu6-drivers repository, as well as an extra
> https://github.com/intel/ivsc-driver for Intel Vision Sensing
> Controller(IVSC).
> 
> [Test Case]
> 
> This depends on an integral of enablement components inclusive of the
> kernel drivers that are being proposed, firmware, updates for the
> userspace camera hardware abstration layer library and a gstreamer
> element as what we have for Tiger Lake platforms.
> 
> Due to previous regression on another TGL-based SKU, reboot stress
> tests were also enrolled on following platforms/SKUs:
> 
>   * TGL/ov01a1s sensor, SKU 2
>   * TGL/ov01a1s sensor, SKU 3
>   * TGL/hm11b1 sensor
>   * Tributo
>   * AndrewsMLK
> 
> [Where problems could occur]
> 
> It's confirmed Intel IPU6 MIPI camera doesn't support suspend at
> streaming.
> 
> It's also a known issue that we don't have support on IPU6 TGL
> platforms as this initial kernel 5.15 porting. This is being worked
> on by the vendor.
> 
> [Other Info]
> 
> V7: Drop previous Acked-By, Signed-off-by from commit messages.
> 
> V6: Added additional commits for the stability issue that regressed in
>     Ubuntu-5.15.0-28.29 and reverted in Ubuntu-5.15.0-29.30.
> 
> V5: correct wrong branch/repo generated in previous rev
> 
> V4: drop obsoleted cflags manipulation and fix UBSAN warnings
> 
> V3: build only on amd64 and add config annotations
> 
> V2: no change rebase only.

I've looked quickly at all the code, of course it's quite difficult to
review the code itself, but I didn't spot any obvious errors. I see
that there's a lot of importing stuff and dropping what we don't need,
I'm wondering if it's be better to squash some of these commits
together into a single initial import SAUCE patch, but maybe this way is
better to keep track of the upstream commits and figure out from where
we started.

A few comments below.

1) In the first set of commits:

 1f69ec679b19 UBUNTU: SAUCE: IPU driver release WW14
 7d3cff6e365e UBUNTU: SAUCE: IPU driver release WW04
 a5733bc898ab UBUNTU: SAUCE: IPU driver release WW52
 db472c127487 UBUNTU: SAUCE: IPU driver release WW48 with MCU
 8d6d4af24f5b UBUNTU: SAUCE: IPU driver release WW48
 07e7d9202f9b UBUNTU: SAUCE: intel ipu drivers first release

it would be nice to know what kind of backport activity was required, I see
that you pretty much imported the initial code from
github.com/intel/ipu6-drivers, what kind of adjustment you had to do to
apply this code to the jammy kernel? Just a few context adjustments or
you had to fix some ABI changes?

2) I think I've asked this before, but who's going to maintain this? Do
we need to actively keep track of github.com/intel/ipu6-drivers and
apply stable fixes in the future? Is there any plan to merge this
upstream?

3) Which commits have been added to address the regressions of
Ubuntu-5.15.0-28.29? Just curious to see what was the problem and maybe
check for similar patterns in the code.

Apart than that the code seems pretty well self-contained, even if it
huge and I'm still worried about maintenance / security fixes, but
overall I think we can apply it, so:

Acked-by: Andrea Righi <andrea.righi at canonical.com>