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

From: Marijn Suijten
Date: Sat Oct 01 2022 - 15:08:42 EST


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@xxxxxxxxxxxxxx>
---
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