On Sun, Jan 08, 2023 at 01:30:44PM +0200, Juha-Pekka Heikkila wrote:
> intel_adjusted_rate() didn't take into account src rectangle
> can be less than 1 in with or height.
Thanks for catching this.
> Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_atomic_plane.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> index 10e1fc9d0698..cd24d069b6eb 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> @@ -144,7 +144,7 @@ unsigned int intel_adjusted_rate(const struct drm_rect *src,
> const struct drm_rect *dst,
> unsigned int rate)
> {
> - unsigned int src_w, src_h, dst_w, dst_h;
> + unsigned int src_w, src_h, dst_w, dst_h, dst_wh;
>
> src_w = drm_rect_width(src) >> 16;
> src_h = drm_rect_height(src) >> 16;
> @@ -155,8 +155,10 @@ unsigned int intel_adjusted_rate(const struct drm_rect *src,
> dst_w = min(src_w, dst_w);
> dst_h = min(src_h, dst_h);
>
> - return DIV_ROUND_UP_ULL(mul_u32_u32(rate, src_w * src_h),
> - dst_w * dst_h);
> + /* in case src contained only fractional part */
> + dst_wh = max(dst_w * dst_h, 1U);
> +
> + return DIV_ROUND_UP_ULL(mul_u32_u32(rate, src_w * src_h), dst_wh);
The div-by-zero is avoided, but we'd return a 0 rate which doesn't look
ok to me. I'd round up instead of down when converting src_w/h from
fixed point to int above.
> }
>
> unsigned int intel_plane_pixel_rate(const struct intel_crtc_state *crtc_state,
> --
> 2.39.0
>
