Re: [PATCH] Input: synaptics-rmi4 - Fix error handling in I2C transport driver

[Guenter Roeck]

On 10/01/2016 10:27 AM, Andrew Duggan wrote:
> On Fri, Sep 30, 2016, at 08:44 PM, Guenter Roeck wrote:
> > On 09/30/2016 04:02 PM, Dmitry Torokhov wrote:
> > > On Fri, Sep 30, 2016 at 03:54:03PM -0700, Dmitry Torokhov wrote:
> > > > On Thu, Sep 29, 2016 at 10:55:40AM -0700, Bjorn Andersson wrote:
> > > > > On Wed 28 Sep 17:37 PDT 2016, Guenter Roeck wrote:
> > > > >
> > > > > > Instantiating the rmi4 I2C transport driver without interrupts assigned
> > > > > > (for example using manual i2c instantiation from the command line)
> > > > > > caused the driver to fail to load, but it does not clean up its
> > > > > > regulator or transport device registrations. Result is a crash at a later
> > > > > > time, for example when rebooting the system.
> > > > > >
> > > > > > Fixes: 946c8432aab0 ("Input: synaptics-rmi4 - support regulator supplies")
> > > > >
> > > > > Sorry for that.
> > > > >
> > > > > > Fixes: fdf51604f104 ("Input: synaptics-rmi4 - add I2C transport driver")
> > > > > > Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> > > > >
> > > > > Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> > > >
> > > > Applied, thank you.
> > >
> > > I take it back. rmi_i2c_init_irq() uses devm* so this whole thing mixes
> > > up devm* and manual unregistering and unwind order is completely
> > > broken.
> > Oops ...
> >
> > > 1. Why do we register interrupt from transport drivers and not make it
> > > part of rmi_register_transport_device()?
>
> Not all RMI devices will have access to interrupts (ie HID and SMBus).
> The same goes for regulators. Here is a reference to a previous
> discussion regarding both:
> https://lkml.org/lkml/2016/5/9/1055
>
> > rmi_register_transport_device() doesn't take dev as parameter.
> >
> > > 2. If we need to use some non-devm-ised resources we should use
> > > devm_add_action[_or_reset] to work these operations into devm stream.
>
> Since the regulator functions have their own devm_ versions I would
> suggest switching to those functions to avoid dealing with
> unregistering.
Maybe I am missing something, but I don't see a devm_regulator_bulk_enable().
devm_regulator_bulk_get() is already used.

Guenter

> Registering and unregistering the transport device is a bit more
> complicated since these functions add and put the rmi_dev device. But,
> it sounds like we can handle the unregister using
> devm_add_action_or_reset().