2024-03-16 16:26:13

by Arthur Grillo

Subject: [PATCH v2] drm: Fix drm_fixp2int_round() making it add 0.5

As well noted by Pekka[1], the rounding of drm_fixp2int_round is wrong.
To round a number, you need to add 0.5 to the number and floor that,
drm_fixp2int_round() is adding 0.0000076. Make it add 0.5.

[1]: https://lore.kernel.org/all/[email protected]/

Fixes: 8b25320887d7 ("drm: Add fixed-point helper to get rounded integer values")
Suggested-by: Pekka Paalanen <[email protected]>
Reviewed-by: Harry Wentland <[email protected]>
Signed-off-by: Arthur Grillo <[email protected]>
---
Changes in v2:
- Add Fixes tag (Melissa Wen)
- Remove DRM_FIXED_POINT_HALF (Melissa Wen)
- Link to v1: https://lore.kernel.org/all/[email protected]/
---
include/drm/drm_fixed.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h
index 0c9f917a4d4b..81572d32db0c 100644
--- a/include/drm/drm_fixed.h
+++ b/include/drm/drm_fixed.h
@@ -71,7 +71,6 @@ static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
}

#define DRM_FIXED_POINT 32
-#define DRM_FIXED_POINT_HALF 16
#define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT)
#define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1)
#define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK)
@@ -90,7 +89,7 @@ static inline int drm_fixp2int(s64 a)

static inline int drm_fixp2int_round(s64 a)
{
- return drm_fixp2int(a + (1 << (DRM_FIXED_POINT_HALF - 1)));
+ return drm_fixp2int(a + DRM_FIXED_ONE / 2);
}

static inline int drm_fixp2int_ceil(s64 a)

---
base-commit: f89632a9e5fa6c4787c14458cd42a9ef42025434
change-id: 20240315-drm_fixed-c680ba078ecb

Best regards,
--
Arthur Grillo <[email protected]>

2024-03-17 17:52:20

by Melissa Wen

Subject: Re: [PATCH v2] drm: Fix drm_fixp2int_round() making it add 0.5

On 03/16, Arthur Grillo wrote:
> As well noted by Pekka[1], the rounding of drm_fixp2int_round is wrong.
> To round a number, you need to add 0.5 to the number and floor that,
> drm_fixp2int_round() is adding 0.0000076. Make it add 0.5.
>
> [1]: https://lore.kernel.org/all/[email protected]/
>
> Fixes: 8b25320887d7 ("drm: Add fixed-point helper to get rounded integer values")
> Suggested-by: Pekka Paalanen <[email protected]>
> Reviewed-by: Harry Wentland <[email protected]>
> Signed-off-by: Arthur Grillo <[email protected]>

Great, thanks!

Reviewed-by: Melissa Wen <[email protected]>

I'll apply to drm-misc-next.

Melissa

> ---
> Changes in v2:
> - Add Fixes tag (Melissa Wen)
> - Remove DRM_FIXED_POINT_HALF (Melissa Wen)
> - Link to v1: https://lore.kernel.org/all/[email protected]/
> ---
> include/drm/drm_fixed.h | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h
> index 0c9f917a4d4b..81572d32db0c 100644
> --- a/include/drm/drm_fixed.h
> +++ b/include/drm/drm_fixed.h
> @@ -71,7 +71,6 @@ static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
> }
>
> #define DRM_FIXED_POINT 32
> -#define DRM_FIXED_POINT_HALF 16
> #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT)
> #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1)
> #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK)
> @@ -90,7 +89,7 @@ static inline int drm_fixp2int(s64 a)
>
> static inline int drm_fixp2int_round(s64 a)
> {
> - return drm_fixp2int(a + (1 << (DRM_FIXED_POINT_HALF - 1)));
> + return drm_fixp2int(a + DRM_FIXED_ONE / 2);
> }
>
> static inline int drm_fixp2int_ceil(s64 a)
>
> ---
> base-commit: f89632a9e5fa6c4787c14458cd42a9ef42025434
> change-id: 20240315-drm_fixed-c680ba078ecb
>
> Best regards,
> --
> Arthur Grillo <[email protected]>
>

2024-03-17 21:28:42

by Maíra Canal

Subject: Re: [PATCH v2] drm: Fix drm_fixp2int_round() making it add 0.5

Hi Melissa,

On 3/17/24 14:50, Melissa Wen wrote:
> On 03/16, Arthur Grillo wrote:
>> As well noted by Pekka[1], the rounding of drm_fixp2int_round is wrong.
>> To round a number, you need to add 0.5 to the number and floor that,
>> drm_fixp2int_round() is adding 0.0000076. Make it add 0.5.
>>
>> [1]: https://lore.kernel.org/all/[email protected]/
>>
>> Fixes: 8b25320887d7 ("drm: Add fixed-point helper to get rounded integer values")
>> Suggested-by: Pekka Paalanen <[email protected]>
>> Reviewed-by: Harry Wentland <[email protected]>
>> Signed-off-by: Arthur Grillo <[email protected]>
>
> Great, thanks!
>
> Reviewed-by: Melissa Wen <[email protected]>
>
> I'll apply to drm-misc-next.

Shouldn't this patch be applied in drm-misc-fixes?

Best Regards,
- Maíra

>
> Melissa
>
>> ---
>> Changes in v2:
>> - Add Fixes tag (Melissa Wen)
>> - Remove DRM_FIXED_POINT_HALF (Melissa Wen)
>> - Link to v1: https://lore.kernel.org/all/[email protected]/
>> ---
>> include/drm/drm_fixed.h | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h
>> index 0c9f917a4d4b..81572d32db0c 100644
>> --- a/include/drm/drm_fixed.h
>> +++ b/include/drm/drm_fixed.h
>> @@ -71,7 +71,6 @@ static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
>> }
>>
>> #define DRM_FIXED_POINT 32
>> -#define DRM_FIXED_POINT_HALF 16
>> #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT)
>> #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1)
>> #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK)
>> @@ -90,7 +89,7 @@ static inline int drm_fixp2int(s64 a)
>>
>> static inline int drm_fixp2int_round(s64 a)
>> {
>> - return drm_fixp2int(a + (1 << (DRM_FIXED_POINT_HALF - 1)));
>> + return drm_fixp2int(a + DRM_FIXED_ONE / 2);
>> }
>>
>> static inline int drm_fixp2int_ceil(s64 a)
>>
>> ---
>> base-commit: f89632a9e5fa6c4787c14458cd42a9ef42025434
>> change-id: 20240315-drm_fixed-c680ba078ecb
>>
>> Best regards,
>> --
>> Arthur Grillo <[email protected]>
>>

2024-03-19 14:25:02

by Melissa Wen

Subject: Re: [PATCH v2] drm: Fix drm_fixp2int_round() making it add 0.5

On 03/17, Ma?ra Canal wrote:
> Hi Melissa,
>
> On 3/17/24 14:50, Melissa Wen wrote:
> > On 03/16, Arthur Grillo wrote:
> > > As well noted by Pekka[1], the rounding of drm_fixp2int_round is wrong.
> > > To round a number, you need to add 0.5 to the number and floor that,
> > > drm_fixp2int_round() is adding 0.0000076. Make it add 0.5.
> > >
> > > [1]: https://lore.kernel.org/all/[email protected]/
> > >
> > > Fixes: 8b25320887d7 ("drm: Add fixed-point helper to get rounded integer values")
> > > Suggested-by: Pekka Paalanen <[email protected]>
> > > Reviewed-by: Harry Wentland <[email protected]>
> > > Signed-off-by: Arthur Grillo <[email protected]>
> >
> > Great, thanks!
> >
> > Reviewed-by: Melissa Wen <[email protected]>
> >
> > I'll apply to drm-misc-next.
>
> Shouldn't this patch be applied in drm-misc-fixes?

After discussions on IRC, I applied to drm-misc-next-fixes, since we are
in a merge window.

Thanks,

Melissa

>
> Best Regards,
> - Ma?ra
>
> >
> > Melissa
> >
> > > ---
> > > Changes in v2:
> > > - Add Fixes tag (Melissa Wen)
> > > - Remove DRM_FIXED_POINT_HALF (Melissa Wen)
> > > - Link to v1: https://lore.kernel.org/all/[email protected]/
> > > ---
> > > include/drm/drm_fixed.h | 3 +--
> > > 1 file changed, 1 insertion(+), 2 deletions(-)
> > >
> > > diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h
> > > index 0c9f917a4d4b..81572d32db0c 100644
> > > --- a/include/drm/drm_fixed.h
> > > +++ b/include/drm/drm_fixed.h
> > > @@ -71,7 +71,6 @@ static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
> > > }
> > > #define DRM_FIXED_POINT 32
> > > -#define DRM_FIXED_POINT_HALF 16
> > > #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT)
> > > #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1)
> > > #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK)
> > > @@ -90,7 +89,7 @@ static inline int drm_fixp2int(s64 a)
> > > static inline int drm_fixp2int_round(s64 a)
> > > {
> > > - return drm_fixp2int(a + (1 << (DRM_FIXED_POINT_HALF - 1)));
> > > + return drm_fixp2int(a + DRM_FIXED_ONE / 2);
> > > }
> > > static inline int drm_fixp2int_ceil(s64 a)
> > >
> > > ---
> > > base-commit: f89632a9e5fa6c4787c14458cd42a9ef42025434
> > > change-id: 20240315-drm_fixed-c680ba078ecb
> > >
> > > Best regards,
> > > --
> > > Arthur Grillo <[email protected]>
> > >