From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
To: "Pali Rohár" <pali.rohar@gmail.com>
Cc: "Andy Shevchenko" <andy.shevchenko@gmail.com>,
"Dmitry Torokhov" <dmitry.torokhov@gmail.com>,
"Michał Kępień" <kernel@kempniu.pl>,
"Jean Delvare" <jdelvare@suse.com>,
"Wolfram Sang" <wsa@the-dreams.de>,
"Steven Honeyman" <stevenhoneyman@gmail.com>,
"Valdis Kletnieks" <Valdis.Kletnieks@vt.edu>,
"Jochen Eisinger" <jochen@penguin-breeder.org>,
"Gabriele Mazzotta" <gabriele.mzt@gmail.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Mario Limonciello" <Mario_Limonciello@dell.com>,
"Alex Hung" <alex.hung@canonical.com>,
"Takashi Iwai" <tiwai@suse.de>,
linux-i2c@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Platform Driver" <platform-driver-x86@vger.kernel.org>
Subject: Re: [PATCH] i2c: i801: Register optional lis3lv02d i2c device on Dell machines
Date: Wed, 4 Jan 2017 13:33:32 +0100 [thread overview]
Message-ID: <20170104123332.GU5767@mail.corp.redhat.com> (raw)
In-Reply-To: <20170104113500.GF3499@pali>
On Jan 04 2017 or thereabouts, Pali Rohár wrote:
> On Wednesday 04 January 2017 11:25:44 Benjamin Tissoires wrote:
> > On Jan 04 2017 or thereabouts, Andy Shevchenko wrote:
> > > On Tue, Jan 3, 2017 at 10:39 PM, Pali Rohár <pali.rohar@gmail.com> wrote:
> > > >
> > > > With Michał we already discussed about it, see emails. Basically you can
> > > > enable/disable kernel modules at compile time or blacklist at runtime
> > > > (or even chose what will be compiled into vmlinux and what as external
> > > > .ko module). Some distributions blacklist i2c-i801.ko module...
> > >
> > > But you understand that any of compile/not compile is not an option, right?
> > > The case which we face will be both of them, if possible, will be
> > > compiled as modules.
> > >
> > > Blacklisting means making your problem the actual user's one. Not good.
> > >
> > > > And
> > > > there can be also problem with initialization of i2c-i801 driver (fix is
> > > > in commit a7ae81952cda, but does not have to work at every time!). So
> > > > that move on whitelisted machines can potentially cause disappearance of
> > > > /dev/freefall and users will not have hdd protection which is currently
> > > > working.
> > >
> >
> > I am seeing the same issues with psmouse and SMBus touchpads. The PS/2
> > device knows about the availability of a better but unlisted device at
> > the ACPI level.
> >
> > The way I solved this to not have to deal with compile/not compile and
> > runtime errors is the same way Wolfram told you about: bus notifiers.
> > I also use an intermediate platform driver to not add i2c dependency on
> > psmouse.
> >
> > For you the solution would be:
> > - In dell-smo8800, after checking the whitelist, add a platform driver
> > "dell-lis3lv02d-platform", and add in the platform_data the I2C address
> > of the chip.
> > - create a new driver dell-lis3lv02d-platform.ko which listens for the
> > i2c bus creation and registers the lis3lv02d I2C node when it sees a
> > matching adapter. (see [1] for my solution)
> > - in dell-lis3lv02d-platform.ko make sure to set the irq to -ENOENT so
> > that lis3lv02d.ko doesn't create /dev/freefall which will still be
> > handled by ACPI.
> >
> > How does that sound?
>
> Yes, something like this was already suggested. But it is more
> complicated as my approach and less error prone... See my notes in
> previous emails.
Sorry but I can't find your notes about errors in your previous emails.
This solution indeed is a little bit more complex than just adding the
bits in i2c-i801, but I don't really see the reason for an *adapter*
driver to instantiate specific *clients* depending on some DMI
matching.
It's a platform issue, so it should be solved at a platform level, not
at the i2c adapter level.
Plus the bus notifier solutions guarantees plain separation between the
elements and prevents any conflicts, with or without compile guards.
>
> My current path (after fixing IRQ to -1) is smaller more intuitive and
This will only fix the fact that you have 2 concurrent drivers on the
same resource (freefall), not the fact that the global design of having
2 drivers which do not cooperate is wrong.
> do not introduce new complicated parts like bus notifier and new "fake"
> i2c driver...
It's not a "fake i2c driver". It's a platform driver. If you don't like
the idea of the platform driver, just add the bus notifier code in
dell-smo8800, but this will pull a new dependency on I2C in this ACPI
driver.
Cheers,
Benjamin
> > [1] https://github.com/bentiss/linux/blob/synaptics-rmi4-v4.9-rc7+/drivers/input/rmi4/rmi_platform.c
>
> --
> Pali Rohár
> pali.rohar@gmail.com
next prev parent reply other threads:[~2017-01-04 12:34 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-27 12:52 [PATCH] i2c: i801: Register optional lis3lv02d i2c device on Dell machines Pali Rohár
2016-12-27 13:43 ` Wolfram Sang
2016-12-27 13:51 ` Pali Rohár
2016-12-27 22:15 ` Andy Shevchenko
2016-12-27 22:41 ` Valdis.Kletnieks
2016-12-28 7:55 ` Andy Shevchenko
2016-12-28 9:05 ` Pali Rohár
2016-12-28 14:03 ` Wolfram Sang
2016-12-29 4:37 ` Valdis.Kletnieks
2016-12-28 8:38 ` Pali Rohár
2016-12-28 14:02 ` Wolfram Sang
2017-01-04 9:45 ` Jean Delvare
2016-12-29 8:29 ` Michał Kępień
2016-12-29 9:00 ` Pali Rohár
2016-12-29 13:47 ` Michał Kępień
2016-12-29 14:17 ` Pali Rohár
2016-12-29 21:09 ` Michał Kępień
2016-12-29 21:28 ` Pali Rohár
2017-01-03 9:06 ` Benjamin Tissoires
2017-01-03 9:23 ` Pali Rohár
2017-01-03 18:38 ` Dmitry Torokhov
2017-01-03 18:50 ` Pali Rohár
2017-01-03 18:58 ` Mario.Limonciello
2017-01-03 19:48 ` Dmitry Torokhov
2017-01-03 20:05 ` Pali Rohár
2017-01-03 20:24 ` Dmitry Torokhov
2017-01-03 20:39 ` Pali Rohár
2017-01-03 20:59 ` Dmitry Torokhov
2017-01-04 8:18 ` Pali Rohár
2017-01-04 9:05 ` Benjamin Tissoires
2017-01-04 9:18 ` Pali Rohár
2017-01-04 10:13 ` Benjamin Tissoires
2017-01-04 10:21 ` Pali Rohár
2017-01-04 10:32 ` Benjamin Tissoires
2017-01-04 11:22 ` Pali Rohár
2017-01-04 12:00 ` Pali Rohár
2017-01-04 13:02 ` Benjamin Tissoires
2017-01-04 16:06 ` Pali Rohár
2017-01-04 17:39 ` Benjamin Tissoires
2017-01-04 17:46 ` Wolfram Sang
2017-01-04 17:54 ` Dmitry Torokhov
2017-01-04 21:49 ` Benjamin Tissoires
2017-01-04 21:55 ` Dmitry Torokhov
2017-01-04 21:55 ` Wolfram Sang
2017-01-04 22:00 ` Dmitry Torokhov
2017-01-04 22:03 ` Dmitry Torokhov
2017-01-05 2:20 ` [PATCH] i2c: do not enable fall back to Host Notify by default kbuild test robot
2017-01-05 2:21 ` kbuild test robot
2017-01-05 8:54 ` [PATCH] i2c: i801: Register optional lis3lv02d i2c device on Dell machines Pali Rohár
2017-01-05 9:26 ` Benjamin Tissoires
2017-01-04 18:50 ` Jean Delvare
2017-01-04 9:53 ` Andy Shevchenko
2017-01-04 10:25 ` Benjamin Tissoires
2017-01-04 11:35 ` Pali Rohár
2017-01-04 12:33 ` Benjamin Tissoires [this message]
2017-01-03 21:29 ` Benjamin Tissoires
2017-01-04 6:36 ` Dmitry Torokhov
2017-01-04 9:13 ` Benjamin Tissoires
2017-01-04 9:25 ` Pali Rohár
2017-01-03 20:20 ` Andy Shevchenko
2017-01-04 10:18 ` Jean Delvare
2017-01-07 12:49 ` Wolfram Sang
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