[PATCH v4 7/8] drm/i915/lobf: Add mutex for alpm update

[Dan Carpenter]

Hi Animesh,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Animesh-Manna/drm-i915-lobf-Add-lobf-enablement-in-post-plane-update/20250224-221647
base:   v6.14-rc4
patch link:    https://lore.kernel.org/r/20250224080847.326350-8-animesh.manna%40intel.com
patch subject: [PATCH v4 7/8] drm/i915/lobf: Add mutex for alpm update
config: i386-randconfig-141-20250225 (https://download.01.org/0day-ci/archive/20250226/202502261244.aUuaLdTn-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp at intel.com>
| Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
| Closes: https://lore.kernel.org/r/202502261244.aUuaLdTn-lkp@intel.com/

smatch warnings:
drivers/gpu/drm/i915/display/intel_alpm.c:548 intel_alpm_disable() warn: inconsistent returns '&intel_dp->alpm_parameters.lock'.

vim +548 drivers/gpu/drm/i915/display/intel_alpm.c

026d6557dc2749d Animesh Manna 2025-02-24  527  void intel_alpm_disable(struct intel_dp *intel_dp)
026d6557dc2749d Animesh Manna 2025-02-24  528  {
026d6557dc2749d Animesh Manna 2025-02-24  529  	struct intel_display *display = to_intel_display(intel_dp);
026d6557dc2749d Animesh Manna 2025-02-24  530  	enum transcoder cpu_transcoder = intel_dp->alpm_parameters.transcoder;
026d6557dc2749d Animesh Manna 2025-02-24  531  
026d6557dc2749d Animesh Manna 2025-02-24  532  	if (DISPLAY_VER(display) < 20)
026d6557dc2749d Animesh Manna 2025-02-24  533  		return;
026d6557dc2749d Animesh Manna 2025-02-24  534  
737b2873a48f3ab Animesh Manna 2025-02-24  535  	mutex_lock(&intel_dp->alpm_parameters.lock);
737b2873a48f3ab Animesh Manna 2025-02-24  536  
026d6557dc2749d Animesh Manna 2025-02-24  537  	if (!(intel_de_read(display, ALPM_CTL(display, cpu_transcoder)) & ALPM_CTL_ALPM_ENABLE))
026d6557dc2749d Animesh Manna 2025-02-24  538  		return;

mutex_unlock(&intel_dp->alpm_parameters.lock) before the return

026d6557dc2749d Animesh Manna 2025-02-24  539  
026d6557dc2749d Animesh Manna 2025-02-24  540  	intel_de_rmw(display, ALPM_CTL(display, cpu_transcoder),
026d6557dc2749d Animesh Manna 2025-02-24  541  		     ALPM_CTL_ALPM_ENABLE | ALPM_CTL_LOBF_ENABLE |
026d6557dc2749d Animesh Manna 2025-02-24  542  		     ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
026d6557dc2749d Animesh Manna 2025-02-24  543  
026d6557dc2749d Animesh Manna 2025-02-24  544  	intel_de_rmw(display,
026d6557dc2749d Animesh Manna 2025-02-24  545  		     PORT_ALPM_CTL(cpu_transcoder),
026d6557dc2749d Animesh Manna 2025-02-24  546  		     PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
737b2873a48f3ab Animesh Manna 2025-02-24  547  
737b2873a48f3ab Animesh Manna 2025-02-24 @548  	mutex_unlock(&intel_dp->alpm_parameters.lock);
026d6557dc2749d Animesh Manna 2025-02-24  549  }

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