[PATCH 1/5] drm/msm/dsi: Remove useless math in DSC calculation

Marijn Suijten marijn.suijten at somainline.org
Sat Oct 1 19:08:03 UTC 2022


Multiplying a value by 2 and adding 1 to it always results in a value
that is uneven, and that 1 gets truncated immediately when performing
integer division by 2 again.  There is no "rounding" possible here.

Fixes: b9080324d6ca ("drm/msm/dsi: add support for dsc data")
Signed-off-by: Marijn Suijten <marijn.suijten at somainline.org>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 8e4bc586c262..e05bae647431 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1864,12 +1864,7 @@ static int dsi_populate_dsc_params(struct drm_dsc_config *dsc)
 	data = 2048 * (dsc->rc_model_size - dsc->initial_offset + num_extra_mux_bits);
 	dsc->slice_bpg_offset = DIV_ROUND_UP(data, groups_total);
 
-	/* bpp * 16 + 0.5 */
-	data = dsc->bits_per_pixel * 16;
-	data *= 2;
-	data++;
-	data /= 2;
-	target_bpp_x16 = data;
+	target_bpp_x16 = dsc->bits_per_pixel * 16;
 
 	data = (dsc->initial_xmit_delay * target_bpp_x16) / 16;
 	final_value =  dsc->rc_model_size - data + num_extra_mux_bits;
-- 
2.37.3



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