On Sun, Mar 14, 2021 at 05:01:24PM +0100, Greg KH wrote:
> On Sun, Mar 14, 2021 at 08:59:41AM -0600, Edmundo Carmona Antoranz wrote:
> > Since its introduction in 5449c685a4b3 (Staging: Add pristine
> > upstream vt6655 driver sources, 2009-04-25), the values
> > stored in variable byData have never been read in the macro
> > PCAvDelayByIO. By removing it, we are getting rid of a warning:
> >
> > drivers/staging/vt6655/upc.h:45:16: warning: variable ‘byData’ set but not used [-Wunused-but-set-variable]
> >
> > Signed-off-by: Edmundo Carmona Antoranz <eantoranz@xxxxxxxxx>
> > ---
> > drivers/staging/vt6655/upc.h | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/staging/vt6655/upc.h b/drivers/staging/vt6655/upc.h
> > index e086ec6e77f7..f00d0fd90003 100644
> > --- a/drivers/staging/vt6655/upc.h
> > +++ b/drivers/staging/vt6655/upc.h
> > @@ -42,14 +42,13 @@
> >
> > #define PCAvDelayByIO(uDelayUnit) \
> > do { \
> > - unsigned char byData; \
> > unsigned long ii; \
> > \
> > if (uDelayUnit <= 50) { \
> > udelay(uDelayUnit); \
> > } else { \
> > for (ii = 0; ii < (uDelayUnit); ii++) \
> > - byData = inb(0x61); \
> > + inb(0x61); \
>
> Are you sure that the compiler does not make the inb() now go away?
>
This is safe. The compiler can't remove it.
regards,
dan carpenter
