ddcci-dkms FTBS with linux 6.8 on noble

[Andrea Righi]

[Impact]

Trying to build ddcci-dkms with the latest noble 6.8 kernel results in the following build error:

/var/lib/dkms/ddcci/0.4.4/build/ddcci/ddcci.c:1831:27: error: ‘I2C_CLASS_DDC’ undeclared here (not in a function); did you mean ‘I2C_CLASS_SPD’?
 1831 | .class = I2C_CLASS_DDC,

This happens because the i2c class I2C_CLASS_DDC has been deprecated in the 6.8 kernel:

commit 754bd2fffc913e523d1b9e686e8b1fd3a70d8f7e
Author: Heiner Kallweit <email address hidden>
Date: Thu Nov 23 10:40:25 2023 +0100

    fbdev: remove I2C_CLASS_DDC support

    After removal of the legacy EEPROM driver and I2C_CLASS_DDC support in
    olpc_dcon there's no i2c client driver left supporting I2C_CLASS_DDC.
    Class-based device auto-detection is a legacy mechanism and shouldn't
    be used in new code. So we can remove this class completely now.

    Acked-by: Helge Deller <email address hidden>
    Acked-by: Thomas Zimmermann <email address hidden>
    Signed-off-by: Heiner Kallweit <email address hidden>
    Signed-off-by: Wolfram Sang <email address hidden>

[Fix]

To properly support this driver (ddcci-dkms) we should revert the commit above in the generic kernel, but the effort of maintaining such custom change is probably not worth it (we probably don't want to maintain this in another LTS release).

[Regression potential]

Users that are still relying on this driver may experience regressions. However, considering how old this driver is and also considering the fact that the upstream kernel decided to remove this i2c class, the impact of such regressions should be minimal.

ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: ddcci-dkms 0.4.4-1
ProcVersionSignature: User Name 6.8.0-11.11-generic 6.8.0-rc4
Uname: Linux 6.8.0-11-generic x86_64
ApportVersion: 2.28.0-0ubuntu1
Architecture: amd64
CasperMD5CheckResult: unknown
CloudArchitecture: x86_64
CloudBuildName: server
CloudID: nocloud
CloudName: unknown
CloudPlatform: nocloud
CloudSerial: 20240220
CloudSubPlatform: config-disk (/dev/vdb)
Date: Fri Feb 23 15:04:41 2024
PackageArchitecture: all
ProcEnviron:
 LANG=C.UTF-8
 PATH=(custom, no user)
 SHELL=/bin/bash
 TERM=xterm-256color
 XDG_RUNTIME_DIR=<set>
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: ddcci-driver-linux
UpgradeStatus: No upgrade log present (probably fresh install)