| Message ID | 20230908012616.20654-1-quic_abhinavk@quicinc.com |
|---|---|
| State | Accepted |
| Commit | 95e681ca3b65e4ce3d2537b47672d787b7d30375 |
| Headers | show |
| Series | [v2] drm/msm/dpu: change _dpu_plane_calc_bw() to use u64 to avoid overflow | expand |
On 9/8/23 03:26, Abhinav Kumar wrote: > _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@quicinc.com> Reported-by: Nia Espera <nespera@igalia.com> Tested-by: Nia Espera <nespera@igalia.com> > --- > 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));
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));
_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@quicinc.com> --- drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)