NACK[M]/Cmnt: [PATCH 0/2][SRU][Unstable/Mantic] Support mipi camera on Intel Meteor Lake platform

[You-Sheng Yang]

Hi Stefan,

On Wed, Oct 25, 2023 at 4:07 PM Stefan Bader <stefan.bader at canonical.com> wrote:
>
> On 24.10.23 10:56, You-Sheng Yang wrote:
> > BugLink: https://bugs.launchpad.net/bugs/2031412
> >
> > [Impact]
> >
> > Need kernel driver fixes for int3472/iommu for Intel IPU6 platform on MTL.
> >
> > [Fix]
> >
> > Two fixes in need. One, we need IOMMU passthrough for MTL platform. The other,
> > fix is for handshake pin support for Lattice MIPI aggregator.
> >
> > [Test Case]
> >
> > ```
> > $ sudo dmesg | grep "Passthrough IOMMU for integrated Intel IPU"
> > $ sudo dmesg | grep int3472
> > # should have no "int3472-discrete INT3472:0c: GPIO type 0x12 unknown; the sensor may not work"
> > ```
> >
> > [Where problems could occur]
> >
> > IOMMU Passthrough as necessary to enable IPU6 on Intel platforms, and it has
> > been patching a few generations e.g. Bug 1989041 for Raptor Lake, Bug 1958004
> > for TGL and ADL. As IPU is not an external facing device which is not risky.
> >
> > For INT3472, the proposed patch might receive further updates per current
> > upstream reviewers' opinions.
> >
> > [Other Info]
> >
> > Nominated for linux/mantic and oem-6.5/jammy as they're for MTL.
> >
> > Hao Yao (1):
> >    UBUNTU: SAUCE: platform/x86: int3472: Add handshake GPIO function
> >
> > You-Sheng Yang (1):
> >    UBUNTU: SAUCE: iommu: intel-ipu: use IOMMU passthrough mode for Intel
> >      IPUs on Meteor Lake
> >
> >   drivers/iommu/intel/iommu.c                   | 1 +
> >   drivers/platform/x86/intel/int3472/common.h   | 1 +
> >   drivers/platform/x86/intel/int3472/discrete.c | 5 +++++
> >   3 files changed, 7 insertions(+)
> >
>
> Rejected for the following reasons:
> - Mantic is released and under SRU process

Yes, therefore I'm following the SRU patch fields, and details the
reason we need it.

> - SAUCE patch that does not look to be going upstream

Firstly, this is not the first patch of similar content. We've been
carrying such iommu patches for IPU6 since oem-5.14. Generic kernels
have it as well, so that we don't have oem gap, and users migrated
from oem-5.4, oem-5.17 to hwe/generic kernels may continue to have a
working camera.

And, I shall not speak for Intel, but the IPU6 drivers are being
upstreamed currently. So far the Intel VSC driver, along with the LJCA
aggregator, have been included in v6.6-rcX, and you can find them in
linux-unstable packages right now. Other IPU6 related components, ISYS
specifically, have been under upstream review for a while. PSYS is to
follow under Intel's own schedule. I'm not sure when will these iommu
patches get upstreamed, but maybe, just maybe, before a working ipu
drivers implementation presents in the mainline kernel, they don't
mean much at this moment.

> - no justification why this must be excepted from norm SRU requirements

This is simply a follow-up to previous iommu fixes for IPU6 for a new
Intel Meteor Lake platform as I stated in the body. They're needed as
previous patches are needed.

> -Stefan

-- 
Regards,
You-Sheng Yang