> -----Original Message----- > From: Arnd Bergmann [mailto:arnd@xxxxxxxx] > Sent: Friday, March 25, 2011 9:40 PM > To: Guan Xuetao > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-arch@xxxxxxxxxxxxxxx > Subject: Re: Warning with asm-generic/div64.h > > On Friday 25 March 2011, Guan Xuetao wrote: > > Following warning is generated when using <asm-generic/div64.h> > > > > kernel/power/hibernate.c: In function 'swsusp_show_speed': > > kernel/power/hibernate.c:227: warning: comparison of distinct pointer types lacks a cast > > > > After expanding the do_div() macro, the problem line is: > > > > (void)(((typeof((n)) *)0) == ((uint64_t *)0)); > > > > while the type of n is s64. > > > > I am puzzled with the usage of the problem line. > > > > And how to correct it? > > The purpose of this line is to generate a warning when the input is the > wrong type, as the comment says: > /* The unnecessary pointer compare is there > * to check for type safety (n must be 64bit) Yes, it works. And, I think type s64 should be ok also. > > The macro doesn't work for signed input or for 32 bit input. I'd suggest > fixing the caller to use an unsigned type. Then, Cc: Len Brown <len.brown@xxxxxxxxx> (supporter:SUSPEND TO RAM) Cc: Pavel Machek <pavel@xxxxxx> (supporter:SUSPEND TO RAM) Cc: "Rafael J. Wysocki" <rjw@xxxxxxx> (supporter:SUSPEND TO RAM) Cc: linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx (open list:SUSPEND TO RAM) > > Arnd Thanks, and sorry for replying late. Guan Xuetao _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
