_dpu_plane_calc_bw() uses integer variables to calculate the bandwidth
used during plane bandwidth calculations. However for high resolution
displays this overflows easily and leads to below errors
[dpu error]crtc83 failed performance check -7
Promote the intermediate variables to u64 to avoid overflow.
changes in v2:
- change to u64 where actually needed in the math
Fixes: c33b7c0389e1 ("drm/msm/dpu: add support for clk and bw scaling for display")
Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/32
Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
index c2aaaded07ed..98c1b22e9bca 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c
@@ -119,6 +119,7 @@ static u64 _dpu_plane_calc_bw(const struct dpu_mdss_cfg *catalog,
struct dpu_sw_pipe_cfg *pipe_cfg)
{
int src_width, src_height, dst_height, fps;
+ u64 plane_pixel_rate, plane_bit_rate;
u64 plane_prefill_bw;
u64 plane_bw;
u32 hw_latency_lines;
@@ -136,13 +137,12 @@ static u64 _dpu_plane_calc_bw(const struct dpu_mdss_cfg *catalog,
scale_factor = src_height > dst_height ?
mult_frac(src_height, 1, dst_height) : 1;
- plane_bw =
- src_width * mode->vtotal * fps * fmt->bpp *
- scale_factor;
+ plane_pixel_rate = src_width * mode->vtotal * fps;
+ plane_bit_rate = plane_pixel_rate * fmt->bpp;
- plane_prefill_bw =
- src_width * hw_latency_lines * fps * fmt->bpp *
- scale_factor * mode->vtotal;
+ plane_bw = plane_bit_rate * scale_factor;
+
+ plane_prefill_bw = plane_bw * hw_latency_lines;
if ((vbp+vpw) > hw_latency_lines)
do_div(plane_prefill_bw, (vbp+vpw));
--
2.40.1
