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

[Benjamin Tissoires]

On Oct 18 2017 or thereabouts, Andrew Duggan wrote:
> 
> 
> 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.

Oh, right, you are correct. I didn't paid enough attention and
overlooked the fact that this function was set in struct
rmi_transport_ops only.

Given Hendrick's Tested-by came in as well (thanks for the quick
tests!), this is:
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>

Cheers,
Benjamin

> 
> 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!
> > 
>