linux-kernel - Re: [PATCH v2 04/10] cpufreq: amd-pstate: add debug message while CPPC is supported and disabled by SBIOS

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Date: Tue, 14 May 2024 01:21:46 +0800
From: kernel test robot <lkp@...el.com>
To: Perry Yuan <perry.yuan@....com>, Mario.Limonciello@....com,
	gautham.shenoy@....com, Ray.Huang@....com, Borislav.Petkov@....com
Cc: llvm@...ts.linux.dev, oe-kbuild-all@...ts.linux.dev,
	rafael.j.wysocki@...el.com, Alexander.Deucher@....com,
	Xinmei.Huang@....com, Xiaojian.Du@....com, Li.Meng@....com,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 04/10] cpufreq: amd-pstate: add debug message while
 CPPC is supported and disabled by SBIOS

Hi Perry,

kernel test robot noticed the following build warnings:

[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on rafael-pm/bleeding-edge next-20240513]
[cannot apply to tip/x86/core linus/master v6.9]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Perry-Yuan/cpufreq-amd-pstate-optimize-the-initial-frequency-values-verification/20240513-101217
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/94ad4bca2d8e44a5e53082959220a184c0222e1e.1715356532.git.perry.yuan%40amd.com
patch subject: [PATCH v2 04/10] cpufreq: amd-pstate: add debug message while CPPC is supported and disabled by SBIOS
config: i386-randconfig-013-20240513 (https://download.01.org/0day-ci/archive/20240514/202405140103.onvXHkqE-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240514/202405140103.onvXHkqE-lkp@intel.com/reproduce)

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@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405140103.onvXHkqE-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/cpufreq/amd-pstate.c:1727:26: warning: overlapping comparisons always evaluate to false [-Wtautological-overlap-compare]
    1727 |                                 (c->x86_model > 0x1f && c->x86_model < 0x1f)) {
         |                                  ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
   1 warning generated.


vim +1727 drivers/cpufreq/amd-pstate.c

  1703	
  1704	/**
  1705	 * CPPC function is not supported for family ID 17H with model_ID ranging from 0x10 to 0x2F.
  1706	 * show the debug message that helps to check if the CPU has CPPC support for loading issue.
  1707	 */
  1708	static bool amd_cppc_supported(void)
  1709	{
  1710		struct cpuinfo_x86 *c = &cpu_data(0);
  1711	
  1712		if ((boot_cpu_data.x86 == 0x17) && (boot_cpu_data.x86_model < 0x30)) {
  1713			pr_debug_once("CPPC feature is not supported by the processor\n");
  1714			return false;
  1715		}
  1716	
  1717		/*
  1718		 * If the CPPC flag is disabled in the BIOS for processors that support MSR-based CPPC
  1719		 * the AMD Pstate driver may not function correctly.
  1720		 */
  1721		if (!cpu_feature_enabled(X86_FEATURE_CPPC)) {
  1722			if (cpu_feature_enabled(X86_FEATURE_ZEN1) || cpu_feature_enabled(X86_FEATURE_ZEN2)) {
  1723				if (c->x86_model > 0x60 && c->x86_model < 0xaf)
  1724					goto warn;
  1725			} else if (cpu_feature_enabled(X86_FEATURE_ZEN3) || cpu_feature_enabled(X86_FEATURE_ZEN4)) {
  1726				if ((c->x86_model > 0x00 && c->x86_model < 0x0F) || (c->x86_model > 0x2f && c->x86_model < 0xaf) ||
> 1727					(c->x86_model > 0x1f && c->x86_model < 0x1f)) {
  1728					goto warn;
  1729				}
  1730			} else {
  1731				goto warn;
  1732			}
  1733		}
  1734	
  1735		return true;
  1736	
  1737	warn:
  1738		pr_debug_once("The CPPC feature is supported but currently disabled by the BIOS.\n"
  1739						"Please enable it if your BIOS supports the CPPC option.\n");
  1740		return false;
  1741	}
  1742	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki