From: Lukas Wunner <lukas@wunner.de>
To: Darren Hart <dvhart@infradead.org>
Cc: "Pali Rohár" <pali.rohar@gmail.com>,
"Micha?? K??pie??" <kernel@kempniu.pl>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Matthew Garrett" <mjg59@srcf.ucam.org>,
"Richard Purdie" <rpurdie@rpsys.net>,
"Jacek Anaszewski" <j.anaszewski@samsung.com>,
platform-driver-x86@vger.kernel.org, linux-leds@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 00/16] Common Dell SMBIOS API
Date: Mon, 8 Feb 2016 20:30:07 +0100 [thread overview]
Message-ID: <20160208193007.GA14985@wunner.de> (raw)
In-Reply-To: <20160208192014.GN1779@malice.jf.intel.com>
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.
Best regards,
Lukas
next prev parent reply other threads:[~2016-02-08 19:30 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-22 14:27 [PATCH v2 00/16] Common Dell SMBIOS API Michał Kępień
2016-01-22 14:27 ` [PATCH v2 01/16] dell-laptop: extract SMBIOS-related code to a separate module Michał Kępień
2016-01-24 2:16 ` kbuild test robot
2016-01-26 13:33 ` Michał Kępień
2016-01-22 14:27 ` [PATCH v2 02/16] dell-smbios: rename get_buffer() to dell_smbios_get_buffer() Michał Kępień
2016-01-22 14:27 ` [PATCH v2 03/16] dell-smbios: rename clear_buffer() to dell_smbios_clear_buffer() Michał Kępień
2016-01-22 14:27 ` [PATCH v2 04/16] dell-smbios: rename release_buffer() to dell_smbios_release_buffer() Michał Kępień
2016-01-22 14:27 ` [PATCH v2 05/16] dell-smbios: rename dell_send_request() to dell_smbios_send_request() Michał Kępień
2016-01-22 14:27 ` [PATCH v2 06/16] dell-smbios: don't pass an SMBIOS buffer " Michał Kępień
2016-01-22 14:27 ` [PATCH v2 07/16] dell-smbios: don't return an SMBIOS buffer from dell_smbios_send_request() Michał Kępień
2016-02-08 18:44 ` Darren Hart
2016-02-09 13:27 ` Michał Kępień
2016-02-09 16:50 ` Darren Hart
2016-02-09 17:34 ` Michał Kępień
2016-01-22 14:27 ` [PATCH v2 08/16] dell-smbios: return the SMBIOS buffer from dell_smbios_get_buffer() Michał Kępień
2016-01-22 14:27 ` [PATCH v2 09/16] dell-smbios: make the SMBIOS buffer static Michał Kępień
2016-01-22 14:27 ` [PATCH v2 10/16] dell-smbios: implement new function for finding DMI table 0xDA tokens Michał Kępień
2016-01-22 14:27 ` [PATCH v2 11/16] dell-laptop: use dell_smbios_find_token() instead of find_token_id() Michał Kępień
2016-01-22 14:27 ` [PATCH v2 12/16] dell-laptop: use dell_smbios_find_token() instead of find_token_location() Michał Kępień
2016-01-22 14:27 ` [PATCH v2 13/16] dell-smbios: remove find_token_{id,location}() Michał Kępień
2016-01-22 14:27 ` [PATCH v2 14/16] dell-smbios: make da_tokens static Michał Kępień
2016-01-22 14:27 ` [PATCH v2 15/16] dell-led: use dell_smbios_find_token() for finding mic DMI tokens Michał Kępień
2016-01-22 14:27 ` [PATCH v2 16/16] dell-led: use dell_smbios_send_request() for performing SMBIOS calls Michał Kępień
2016-01-22 14:48 ` [PATCH v2 00/16] Common Dell SMBIOS API Pali Rohár
2016-02-07 20:34 ` Darren Hart
2016-02-08 19:20 ` Darren Hart
2016-02-08 19:29 ` Greg Kroah-Hartman
2016-02-08 20:46 ` Darren Hart
2016-02-08 21:04 ` Pali Rohár
2016-02-08 21:31 ` Darren Hart
2016-02-09 14:15 ` Michał Kępień
2016-02-08 19:30 ` Lukas Wunner [this message]
2016-02-08 20:43 ` Darren Hart
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