Re: [PATCH v2 4/6] drm/i915/gt: add a macro for mock gt wakeref special value and use it

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Wed, Sep 18, 2024 at 08:35:46PM +0300, Jani Nikula wrote:
> Add a dedicated macro for the special mock gt wakeref value, with a cast
> to intel_wakeref_t, instead of assuming you can assign or compare the
> wakeref to -ENODEV directly.
> 
> Arguably the whole thing is a hack that should not exist, but at least
> make it slightly less hacky.

I couldn't agree more

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> 
> Side note: If this value were to ever end up in
> intel_ref_tracker_free(), it would wreak havoc.
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_gt_pm.h            | 6 +++++-
>  drivers/gpu/drm/i915/gt/intel_tlb.c              | 2 +-
>  drivers/gpu/drm/i915/selftests/mock_gem_device.c | 2 +-
>  3 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> index 911fd0160221..fef8d5d288f8 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> @@ -105,9 +105,13 @@ int intel_gt_runtime_resume(struct intel_gt *gt);
>  
>  ktime_t intel_gt_get_awake_time(const struct intel_gt *gt);
>  
> +#define INTEL_WAKEREF_MOCK_GT ((intel_wakeref_t)-ENODEV)
> +
>  static inline bool is_mock_gt(const struct intel_gt *gt)
>  {
> -	return I915_SELFTEST_ONLY(gt->awake == -ENODEV);
> +	BUILD_BUG_ON(INTEL_WAKEREF_DEF == INTEL_WAKEREF_MOCK_GT);
> +
> +	return I915_SELFTEST_ONLY(gt->awake == INTEL_WAKEREF_MOCK_GT);
>  }
>  
>  #endif /* INTEL_GT_PM_H */
> diff --git a/drivers/gpu/drm/i915/gt/intel_tlb.c b/drivers/gpu/drm/i915/gt/intel_tlb.c
> index 756e9ebbc725..2487768bc230 100644
> --- a/drivers/gpu/drm/i915/gt/intel_tlb.c
> +++ b/drivers/gpu/drm/i915/gt/intel_tlb.c
> @@ -122,7 +122,7 @@ void intel_gt_invalidate_tlb_full(struct intel_gt *gt, u32 seqno)
>  {
>  	intel_wakeref_t wakeref;
>  
> -	if (I915_SELFTEST_ONLY(gt->awake == -ENODEV))
> +	if (is_mock_gt(gt))
>  		return;
>  
>  	if (intel_gt_is_wedged(gt))
> diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> index 70f3d7bf47d0..ae57eb03dfca 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> @@ -203,7 +203,7 @@ struct drm_i915_private *mock_gem_device(void)
>  	intel_root_gt_init_early(i915);
>  	mock_uncore_init(&i915->uncore, i915);
>  	atomic_inc(&to_gt(i915)->wakeref.count); /* disable; no hw support */
> -	to_gt(i915)->awake = -ENODEV;
> +	to_gt(i915)->awake = INTEL_WAKEREF_MOCK_GT;
>  	mock_gt_probe(i915);
>  
>  	ret = intel_region_ttm_device_init(i915);
> -- 
> 2.39.2
>