From: Abhinav Kumar Date: Fri, 8 Sep 2023 01:26:16 +0000 (-0700) Subject: drm/msm/dpu: change _dpu_plane_calc_bw() to use u64 to avoid overflow X-Git-Tag: v6.6.7~1743^2~1^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=95e681ca3b65e4ce3d2537b47672d787b7d30375;p=platform%2Fkernel%2Flinux-starfive.git drm/msm/dpu: change _dpu_plane_calc_bw() to use u64 to avoid overflow _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") Reviewed-by: Dmitry Baryshkov Reported-by: Nia Espera Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/32 Tested-by: Nia Espera Patchwork: https://patchwork.freedesktop.org/patch/556288/ Link: https://lore.kernel.org/r/20230908012616.20654-1-quic_abhinavk@quicinc.com Signed-off-by: Abhinav Kumar --- diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c index c2aaade..98c1b22 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));