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@xxxxxxxxx> 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@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
