Thread (2 messages) 2 messages, 1 author, 2021-06-24
DORMANTno replies

[PATCH v2] drm/mediatek: adjust rdma fifo threshold calculate formula

From: Yongqiang Niu <hidden>
Date: 2021-06-24 13:02:14
Also in: dri-devel, linux-devicetree, linux-mediatek, lkml
Subsystem: drm drivers, drm drivers for mediatek, the rest · Maintainers: David Airlie, Simona Vetter, Chun-Kuang Hu, Philipp Zabel, Linus Torvalds

the orginal formula will caused rdma fifo threshold config overflow

Signed-off-by: Yongqiang Niu <redacted>
---
 drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
index 728aaad..bef3f04 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
@@ -164,10 +164,10 @@ void mtk_rdma_config(struct device *dev, unsigned int width,
 	/*
 	 * Enable FIFO underflow since DSI and DPI can't be blocked.
 	 * Keep the FIFO pseudo size reset default of 8 KiB. Set the
-	 * output threshold to 6 microseconds with 7/6 overhead to
-	 * account for blanking, and with a pixel depth of 4 bytes:
+	 * output threshold to 70% of max fifo size to make sure the
+	 * threhold will not overflow
 	 */
-	threshold = width * height * vrefresh * 4 * 7 / 1000000;
+	threshold = rdma_fifo_size * 7 / 10;
 	reg = RDMA_FIFO_UNDERFLOW_EN |
 	      RDMA_FIFO_PSEUDO_SIZE(rdma_fifo_size) |
 	      RDMA_OUTPUT_VALID_FIFO_THRESHOLD(threshold);
-- 
1.8.1.1.dirty
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