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

[Andrew Duggan]

On Sat, Oct 1, 2016, at 10:45 AM, Guenter Roeck wrote:
> 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.
> 

Yeah, I was just double checking that too. You're right, they are
already using the devm version.

Andrew

> 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().
> >