Re: [PATCH] HID: rmi: Check that a device is a RMI device before calling RMI functions

[Andrew Duggan]

On 10/18/2017 07:13 AM, Jiri Kosina wrote:
> On Wed, 18 Oct 2017, Benjamin Tissoires wrote:
>
> > > The hid-rmi driver may handle non rmi devices on composite USB devices.
> > > Callbacks need to make sure that the current device is a RMI device before
> > > calling RMI specific functions. Most callbacks already have this check, but
> > > this patch adds checks to the remaining callbacks.
> > >
> > > Signed-off-by: Andrew Duggan <aduggan@xxxxxxxxxxxxx>
> > > ---
> > > This is the patch which hopefully will address the X1 tablet dock freeze:
> > > http://www.spinics.net/lists/linux-input/msg53582.html
> > >
> > > I was not able to test on a composite USB device so I have not tested confirmed
> > > this will fix the reported issues. But, based on the description I think it will.
> > > I also added a check for rmi_raw_event() since it could be possible that another
> > > hid device using one of the same report IDs as an RMI device could result in calling
> > > into unitialized RMI functions. It was also the only callbacl left not checking the
> > > RMI_DEVICE flag. I wonder if this explains the attach crash.
> > >
> > > Anyway, I would appriciate it if Hendrik or someone else with the device could test this
> > > patch to confirm it fixes the reported behavior.
> > Shouldn't rmi_hid_reset() also get the same check?
> I think so as well.

Since rmi_hid_reset() is only called from with in the RMI4 driver I 
didn't think that it needed a check. All of the functions set in struct 
hid_driver should now check the RMI_DEVICE flag before calling into the 
RMI4 driver. But, if I am missing something we can add additional checks.

Thanks,
Andrew

> >  From what I can see, even if the patch doesn't fix the immediate issue,
> > such a patch should definitively go in as those checks are clearly
> > missing.
> Agreed; however I'd like to get Hendrik's Tested-by: if possible in case
> this really fixes the issue, so I am not merging it right away.
>
> Hendrik, are you by any chance able to test this patch in a reasonable
> timeframe please?
>
> Thanks!