Messages in this thread | | | Date | Mon, 8 Feb 2016 12:43:30 -0800 | From | Darren Hart <> | Subject | Re: [PATCH v2 00/16] Common Dell SMBIOS API |
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On Mon, Feb 08, 2016 at 08:30:07PM +0100, Lukas Wunner wrote: > Hi, > > On Mon, Feb 08, 2016 at 11:20:14AM -0800, Darren Hart wrote: > > My only major concern is module load order dependencies. Inter-module > > dependencies are frowned upon with good reason, the kernel load ordering is > > non-deterministic and it's possible, for example, for dell-laptop to fail to > > find the symbols exported by dell-smbios under certain conditions. > > > > I have worked around this in the past with things like the following: > > > > #ifdef MODULE > > #ifdef CONFIG_FOO_MODULE > > if (request_module("foo")) > > return -ENODEV; > > #endif > > #endif > > > > Something like the above may be necessary for dell-smbios in dell-laptop, > > dell-wmi, and dell-leds now that they depend on the dell-smbios exported > > functions. > > > > Cc Greg in case there is a better way to handle this that I'm not aware of. > > Deferred probing seems to be the preferred way, see e.g.: > https://lists.freedesktop.org/archives/dri-devel/2016-January/098404.html > > (In this example, apple_gmux_present() determines presence of the device > and !vga_switcheroo_handler_flags() determine non-presence of its driver.) > > This will also work if the subsystem depended on is compiled in rather > than in a module.
Ah, interesting. Thanks Lukas. Sounds like we're going to be fine as is with this particular case.
Thanks,
-- Darren Hart Intel Open Source Technology Center
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