Re: [PATCH v2 2/2] clk: tests: Add tests for fractional divisor approximation

From: Frank Oltmanns <frank@oltmanns.dev>
To: kernel test robot <lkp@intel.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>
Cc: oe-kbuild-all@lists.linux.dev, "A.s. Dong" <aisheng.dong@nxp.com>,
	Abel Vesa <abelvesa@kernel.org>,
	Fabio Estevam <festevam@gmail.com>,
	linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
	linux-kernel@vger.kernel.org, NXP Linux Team <linux-imx@nxp.com>,
	Peng Fan <peng.fan@nxp.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Shawn Guo <shawnguo@kernel.org>
Subject: Re: [PATCH v2 2/2] clk: tests: Add tests for fractional divisor approximation
Date: Wed, 14 Jun 2023 10:19:37 +0200	[thread overview]
Message-ID: <87edmeqwva.fsf@oltmanns.dev> (raw)
In-Reply-To: <202306132038.nUB6hmCv-lkp@intel.com>

Hi,

On 2023-06-13 at 20:48:21 +0800, kernel test robot <lkp@intel.com> wrote:
> Hi Frank,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on v6.4-rc6]
> [also build test ERROR on linus/master]
> [cannot apply to clk/clk-next next-20230613]
> [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/Frank-Oltmanns/clk-fractional-divider-Improve-approximation-when-zero-based/20230613-163903
> base:   v6.4-rc6
> patch link:    https://lore.kernel.org/r/20230613083626.227476-3-frank%40oltmanns.dev
> patch subject: [PATCH v2 2/2] clk: tests: Add tests for fractional divisor approximation
> config: csky-randconfig-r011-20230612 (https://download.01.org/0day-ci/archive/20230613/202306132038.nUB6hmCv-lkp@intel.com/config)
> compiler: csky-linux-gcc (GCC) 12.3.0
> reproduce (this is a W=1 build):
>         mkdir -p ~/bin
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         git checkout v6.4-rc6
>         b4 shazam https://lore.kernel.org/r/20230613083626.227476-3-frank@oltmanns.dev
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=csky olddefconfig
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=csky SHELL=/bin/bash
>
> 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@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202306132038.nUB6hmCv-lkp@intel.com/
>
> All errors (new ones prefixed by >>, old ones prefixed by <<):
>
>>> ERROR: modpost: "clk_fractional_divider_general_approximation" [drivers/clk/clk_test.ko] undefined!

The issue seems to be that clk_fractional_divider_general_approximation
is not exported as a symbol, while the config builds the clk_test as a
module:
CONFIG_CLK_KUNIT_TEST=m

If I'm not mistaken, this means that I can't test
clk_fractional_divider_general_approximation directly. Instead I'd have
to test it using clk_fractional_divider_ops.round_rate.

Can someone more knowlegdable than me please confirm if my understanding
is correct?

Thanks,
  Frank