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

[Guenter Roeck]

On 10/01/2016 12:04 PM, Dmitry Torokhov wrote:
> On Sat, Oct 01, 2016 at 10:27:42AM -0700, 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
>
> Yeah, I am wondering if we should not revisit this and have SMBus (and
> possibly HID) actually provide us with an interrupt.
>
> In the meantime we can just ignore interrupt value if it is set to 0.

I have another follow-up patch doing that (I have a test setup which
doesn't support interrupts); I just wasn't sure if there was interest,
so I did not yet send it out. I'll be happy to do that, though I would
prefer to keep it separate (it isn't a bug fix, after all).

Thanks,
Guenter