fix(ccs): handle 1-param pm_runtime_get_if_active (issue #92)

[Till0196]

fix(ccs): handle 1-param pm_runtime_get_if_active (issue #92)

Fixes #92

Problem

v6.8-ccs.patch changes pm_runtime_get_if_active() to its 2-param form for
kernels ≤ 6.8. This is correct for mainline kernels 5.6–6.8, which introduced
the bool ign_usage_count parameter.

However, some distributions backport the simplified 1-param form from
kernel 6.9+ to their 6.8 kernel (e.g. Ubuntu 6.8). On those kernels the patched
2-param call fails to compile:

error: too many arguments to function 'pm_runtime_get_if_active'

Fix

Detect which variant the kernel exposes by matching the prototype pattern
pm_runtime_get_if_active[^)]*bool in include/linux/pm_runtime.h via
make_config_compat.pl. This matches on the presence of a bool second
parameter rather than a specific parameter name, making the check robust
across vendor/backport trees that may rename the parameter:

/* mainline 5.6–6.8: pattern matches → no wrapper needed */
extern int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);

/* 6.9+ and distros that backport the simplification: no match → wrapper needed */
extern int pm_runtime_get_if_active(struct device *dev);

When the pattern is absent (1-param kernel), NEED_PM_RUNTIME_GET_IF_ACTIVE_WRAPPER
is defined and compat.h provides a variadic macro that drops the second argument:

#ifdef NEED_PM_RUNTIME_GET_IF_ACTIVE_WRAPPER
#define pm_runtime_get_if_active(dev, ...) (pm_runtime_get_if_active)(dev)
#endif

The (pm_runtime_get_if_active) notation prevents recursive macro expansion.
A macro is used instead of a static inline wrapper because compat.h is
force-included before kernel headers, so the function is not yet declared at
that point.

v6.8-ccs.patch and v5.6_pm_runtime_get_if_active.patch are left unchanged.

Testing

Verified that the build completes without errors on Ubuntu 6.8.0-107-generic,
which ships the 1-param variant of pm_runtime_get_if_active.

[Copilot]

Pull request overview

This PR fixes build failures on kernels where pm_runtime_get_if_active() has been backported to the newer 1-parameter form (e.g., Ubuntu 6.8), while existing backport patches expect the older 2-parameter form.

Changes:

• Extend make_config_compat.pl to detect whether the kernel headers expose the 2-parameter pm_runtime_get_if_active() variant.
• Add a conditional compat macro in v4l/compat.h to drop the second argument when only the 1-parameter API exists.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
v4l/scripts/make_config_compat.pl	Adds header scanning to decide whether a compat wrapper is needed for pm_runtime_get_if_active().
v4l/compat.h	Provides a conditional macro wrapper to make 2-arg call sites compile against 1-arg kernels.

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