linux-kernel - Re: [PATCH] PM / devfreq: Add support for QCOM devfreq FW

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Message-ID: <201805190032.1PLoraIq%fengguang.wu@intel.com>
Date:   Sat, 19 May 2018 00:59:36 +0800
From:   kbuild test robot <lkp@...el.com>
To:     Saravana Kannan <skannan@...eaurora.org>
Cc:     kbuild-all@...org, MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PM / devfreq: Add support for QCOM devfreq FW

Hi Saravana,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.17-rc5 next-20180517]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Saravana-Kannan/PM-devfreq-Add-support-for-QCOM-devfreq-FW/20180518-230524
config: arm-allmodconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers//devfreq/devfreq_qcom_fw.c: In function 'devfreq_qcom_fw_driver_probe':
>> drivers//devfreq/devfreq_qcom_fw.c:127:26: warning: 'prev_freq' may be used uninitialized in this function [-Wmaybe-uninitialized]
      if (i > 0 && prev_freq == freq)
                   ~~~~~~~~~~^~~~~~~
   drivers//devfreq/devfreq_qcom_fw.c:101:22: note: 'prev_freq' was declared here
     unsigned long freq, prev_freq;
                         ^~~~~~~~~

vim +/prev_freq +127 drivers//devfreq/devfreq_qcom_fw.c

    96	
    97	static int devfreq_qcom_populate_opp(struct platform_device *pdev)
    98	{
    99		struct device *dev = &pdev->dev;
   100		u32 data, src, lval, i;
   101		unsigned long freq, prev_freq;
   102		struct resource *res;
   103		void __iomem *lut_base;
   104	
   105		res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "lut-base");
   106		if (!res) {
   107			dev_err(dev, "Unable to find lut-base!\n");
   108			return -EINVAL;
   109		}
   110	
   111		lut_base = devm_ioremap(dev, res->start, resource_size(res));
   112		if (!lut_base) {
   113			dev_err(dev, "Unable to map lut-base\n");
   114			return -ENOMEM;
   115		}
   116	
   117		for (i = 0; i < LUT_MAX_ENTRIES; i++) {
   118			data = readl_relaxed(lut_base + i * LUT_ROW_SIZE);
   119			src = ((data & GENMASK(31, 30)) >> 30);
   120			lval = (data & GENMASK(7, 0));
   121			freq = src ? XO_RATE * lval : INIT_RATE;
   122	
   123			/*
   124			 * Two of the same frequencies with the same core counts means
   125			 * end of table.
   126			 */
 > 127			if (i > 0 && prev_freq == freq)
   128				break;
   129	
   130			dev_pm_opp_add(&pdev->dev, freq, 0);
   131	
   132			prev_freq = freq;
   133		}
   134	
   135		devm_iounmap(dev, lut_base);
   136	
   137		return 0;
   138	}
   139	

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0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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