| Message ID | 1481895135-11055-1-git-send-email-jean-christophe.trotin@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Jean-Christophe, On Fri, Dec 16, 2016 at 02:32:15PM +0100, Jean-Christophe Trotin wrote: > Correct the calculation of the rounding to nearest aligned value in > the clamp_align() function. For example, clamp_align(1277, 1, 9600, 2) > returns 1276, while it should return 1280. Why should the function return 1280 instead of 1276, which is closer to 1277? > > Signed-off-by: Jean-Christophe Trotin <jean-christophe.trotin@st.com> > --- > drivers/media/v4l2-core/v4l2-common.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c > index 57cfe26a..2970ce7 100644 > --- a/drivers/media/v4l2-core/v4l2-common.c > +++ b/drivers/media/v4l2-core/v4l2-common.c > @@ -315,7 +315,7 @@ static unsigned int clamp_align(unsigned int x, unsigned int min, > > /* Round to nearest aligned value */ > if (align) > - x = (x + (1 << (align - 1))) & mask; > + x = (x + ((1 << align) - 1)) & mask; > > return x; > }
Hi Sakari, Thank you for your answer. You're right: the modification that I proposed, is not correct (I misunderstood the aim of the function); the current clamp_align() is correct and doesn't need any modification. Thus, the patch that I sent, must be ignored. Sorry for the disruption. Regards, Jean-Christophe. On 12/16/2016 02:56 PM, Sakari Ailus wrote: > Hi Jean-Christophe, > > On Fri, Dec 16, 2016 at 02:32:15PM +0100, Jean-Christophe Trotin wrote: >> Correct the calculation of the rounding to nearest aligned value in >> the clamp_align() function. For example, clamp_align(1277, 1, 9600, 2) >> returns 1276, while it should return 1280. > > Why should the function return 1280 instead of 1276, which is closer to > 1277? > >> >> Signed-off-by: Jean-Christophe Trotin <jean-christophe.trotin@st.com> >> --- >> drivers/media/v4l2-core/v4l2-common.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c >> index 57cfe26a..2970ce7 100644 >> --- a/drivers/media/v4l2-core/v4l2-common.c >> +++ b/drivers/media/v4l2-core/v4l2-common.c >> @@ -315,7 +315,7 @@ static unsigned int clamp_align(unsigned int x, unsigned int min, >> >> /* Round to nearest aligned value */ >> if (align) >> - x = (x + (1 << (align - 1))) & mask; >> + x = (x + ((1 << align) - 1)) & mask; >> >> return x; >> } >-- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c index 57cfe26a..2970ce7 100644 --- a/drivers/media/v4l2-core/v4l2-common.c +++ b/drivers/media/v4l2-core/v4l2-common.c @@ -315,7 +315,7 @@ static unsigned int clamp_align(unsigned int x, unsigned int min, /* Round to nearest aligned value */ if (align) - x = (x + (1 << (align - 1))) & mask; + x = (x + ((1 << align) - 1)) & mask; return x; }
Correct the calculation of the rounding to nearest aligned value in the clamp_align() function. For example, clamp_align(1277, 1, 9600, 2) returns 1276, while it should return 1280. Signed-off-by: Jean-Christophe Trotin <jean-christophe.trotin@st.com> --- drivers/media/v4l2-core/v4l2-common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)