5.10-stable review patch. If anyone has any objections, please let me know.
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From: Abhinav Kumar quic_abhinavk@quicinc.com
[ Upstream commit 95e681ca3b65e4ce3d2537b47672d787b7d30375 ]
_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 dmitry.baryshkov@linaro.org Reported-by: Nia Espera nespera@igalia.com Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/32 Tested-by: Nia Espera nespera@igalia.com 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 quic_abhinavk@quicinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 7ea90d25a3b69..8aa9f2335f57a 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c @@ -147,6 +147,7 @@ static void _dpu_plane_calc_bw(struct drm_plane *plane, const struct dpu_format *fmt = NULL; struct dpu_kms *dpu_kms = _dpu_plane_get_kms(plane); 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; @@ -168,13 +169,12 @@ static void _dpu_plane_calc_bw(struct drm_plane *plane, 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;
do_div(plane_prefill_bw, (vbp+vpw));