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[6/7] drm/i915: Switch intel_usecs_to_scanlines() to 64bit maths

Message ID 20240528185647.7765-7-ville.syrjala@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series drm/i915: Cleanups around scanline arithmetic | expand

Commit Message

Ville Syrjala May 28, 2024, 6:56 p.m. UTC 
From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Dotclocks can reach ~1GHz these days, so intel_usecs_to_scanlines(),
with its 32bit maths, is currently limited to a few milliseconds.
I want bigger numbers in DSB selftests, so switch over to 64bit
maths.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_crtc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Jani Nikula May 29, 2024, 9:22 a.m. UTC | #1 
On Tue, 28 May 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Dotclocks can reach ~1GHz these days, so intel_usecs_to_scanlines(),
> with its 32bit maths, is currently limited to a few milliseconds.
> I want bigger numbers in DSB selftests, so switch over to 64bit
> maths.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_crtc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c
> index ca6dc1dc56c8..17edd6099287 100644
> --- a/drivers/gpu/drm/i915/display/intel_crtc.c
> +++ b/drivers/gpu/drm/i915/display/intel_crtc.c
> @@ -454,8 +454,8 @@ int intel_usecs_to_scanlines(const struct drm_display_mode *adjusted_mode,
>  	if (!adjusted_mode->crtc_htotal)
>  		return 1;
>  
> -	return DIV_ROUND_UP(usecs * adjusted_mode->crtc_clock,
> -			    1000 * adjusted_mode->crtc_htotal);
> +	return DIV_ROUND_UP_ULL(mul_u32_u32(usecs, adjusted_mode->crtc_clock),
> +				1000 * adjusted_mode->crtc_htotal);
>  }
>  
>  /**
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c
index ca6dc1dc56c8..17edd6099287 100644
--- a/drivers/gpu/drm/i915/display/intel_crtc.c
+++ b/drivers/gpu/drm/i915/display/intel_crtc.c
@@ -454,8 +454,8 @@  int intel_usecs_to_scanlines(const struct drm_display_mode *adjusted_mode,
 	if (!adjusted_mode->crtc_htotal)
 		return 1;
 
-	return DIV_ROUND_UP(usecs * adjusted_mode->crtc_clock,
-			    1000 * adjusted_mode->crtc_htotal);
+	return DIV_ROUND_UP_ULL(mul_u32_u32(usecs, adjusted_mode->crtc_clock),
+				1000 * adjusted_mode->crtc_htotal);
 }
 
 /**