Apologies for top post, I'm on mobile.

I agree it sounds like a corner case to support someone not compiling dell-laptop, but there are actually desktops and workstations that are also supported by dell-smbios-smm.

But then the intersection of systems supporting only smm and not wmi is very small and wmi will load based on the bus. So I'm in agreement with you.

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From: Hans de Goede <hdegoede@redhat.com>
Sent: Tuesday, June 8, 2021 3:36:27 AM
To: kernel test robot <lkp@intel.com>; Mario Limonciello <mario.limonciello@outlook.com>
Cc: kbuild-all@lists.01.org <kbuild-all@lists.01.org>; clang-built-linux@googlegroups.com <clang-built-linux@googlegroups.com>; linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>
Subject: Re: drivers/platform/x86/dell/dell-smbios-smm.c:27:35: warning: unused variable 'dell_device_table'
 
<replaced Mario's old Dell email address which one which works>

Hi all,

On 6/8/21 12:41 AM, kernel test robot wrote:
> Hi Mario,
>
> FYI, the error/warning still remains.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   614124bea77e452aa6df7a8714e8bc820b489922
> commit: f1e1ea516721d1ea0b21327ff9e6cb2c2bb86e28 platform/x86: Move all dell drivers to their own subdirectory
> date:   4 months ago
> config: x86_64-randconfig-r023-20210608 (attached as .config)
> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project ae973380c5f6be77ce395022be40350942260be9)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install x86_64 cross compiling tool for clang build
>         # apt-get install binutils-x86-64-linux-gnu
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f1e1ea516721d1ea0b21327ff9e6cb2c2bb86e28
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout f1e1ea516721d1ea0b21327ff9e6cb2c2bb86e28
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
>>> drivers/platform/x86/dell/dell-smbios-smm.c:27:35: warning: unused variable 'dell_device_table' [-Wunused-const-variable]
>    static const struct dmi_system_id dell_device_table[] __initconst = {
>                                      ^
>    1 warning generated.
>
>
> vim +/dell_device_table +27 drivers/platform/x86/dell/dell-smbios-smm.c
>
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  26 
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01 @27  static const struct dmi_system_id dell_device_table[] __initconst = {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  28         {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  29                 .ident = "Dell laptop",
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  30                 .matches = {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  31                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  32                         DMI_MATCH(DMI_CHASSIS_TYPE, "8"),
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  33                 },
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  34         },
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  35         {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  36                 .matches = {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  37                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  38                         DMI_MATCH(DMI_CHASSIS_TYPE, "9"), /*Laptop*/
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  39                 },
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  40         },
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  41         {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  42                 .matches = {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  43                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  44                         DMI_MATCH(DMI_CHASSIS_TYPE, "10"), /*Notebook*/
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  45                 },
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  46         },
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  47         {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  48                 .ident = "Dell Computer Corporation",
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  49                 .matches = {
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  50                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  51                         DMI_MATCH(DMI_CHASSIS_TYPE, "8"),
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  52                 },
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  53         },
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  54         { }
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  55  };
> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  56  MODULE_DEVICE_TABLE(dmi, dell_device_table);

Note the MODULE_DEVICE_TABLE() here; and I checked and CONFIG_DMI=y in the config used
here as expected, so this seems like a false-positive warnings, with that said I was
still a bit surprised about the presence of this table since dell-smbios is depended
on by dell-laptop and that has this same table + same extra entries for chassis-type
30, 31 and 32.

Since dell-laptop will already auto-load based on the DMI table in there (which also is
more complete) and since dell-laptop will then bring in the dell-smbios module, the only
scenario I can think of where this DMI table inside dell-smbios-smm.c is useful is if
users have the dell-laptop module disabled and they want to use the sysfs interface
offered by dell-smbios-smm.c. But that seems such a corner case that I believe it
would be fair to tell users to do a modprobe themselves in this case ?

This would allow removing the dupplicate table from dell-smbios-smm.c, which would be
a good thing, because as the differences between the 2 copies which have accumulated
over time show, having the same table in 2 places seems like a bad idea.

Mario, even though you are no longer at Dell, I would still very much appreciate your
thoughts on this.

Regards,

Hans



> 549b4930f05765 drivers/platform/x86/dell-smbios-smm.c Mario Limonciello 2017-11-01  57 
>
> :::::: The code at line 27 was first introduced by commit
> :::::: 549b4930f057658dc50d8010e66219233119a4d8 platform/x86: dell-smbios: Introduce dispatcher for SMM calls
>
> :::::: TO: Mario Limonciello <mario.limonciello@dell.com>
> :::::: CC: Darren Hart (VMware) <dvhart@infradead.org>
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
>