On Fri, Dec 11, 2020 at 06:56:14PM +0200, Sakari Ailus wrote:
On Mon, Nov 23, 2020 at 12:40:18PM +0200, Andy Shevchenko wrote:
> On Sat, Nov 21, 2020 at 04:23:05PM +0800, kernel test robot wrote:
> > All warnings (new ones prefixed by >>):
> > >> drivers/media/pci/intel/ipu3/ipu3-cio2.c:163:56: warning: implicit
conversion from 'unsigned long' to 'u16' (aka 'unsigned short')
changes value from 131072 to 0 [-Wconstant-conversion]
> > entry.second_entry.num_of_pages = CIO2_LOP_ENTRIES *
> > ~
> > 1 warning generated.
> Okay, now we have an interesting case. The IP is quite unlikely be used on
> ARM64, but my patches made the clear picture about use of PAGE_SIZE here.
> So, I see at least the following options to mitigate the above, i.e.:
> 1/ reduce driver scope to X86
> 2/ fix the variables to be wider type to be able to hold PAGE_SIZE > 4k
> 3/ switch to custom PAGE_SIZE / _SHIFT / _MASK and accompanying macros
> And I still consider 3/ is silly move because as we see the driver was
> never assumed to work with big page sizes (besides unsigned short type
> here, PAGE_SHIFT and PAGE_MASK in the original code was as is and on ARM64
> they compiled to 0 values w/o warnings, effectively make the driver
> improperly functioning anyway).
Apologies for the late answer.
I think I'd favour the first option. It's not really useful to be able to
compile this elsewhere; as such the driver doesn't do anything special that
would make it prone to breakage through changes elsewhere.
Would you like to send a patch? :-)
With Best Regards,