[PATCH V4 1/6] drm: bridge: samsung-dsim: fix blanking packet size calculation

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Lucas Stach <l.stach@xxxxxxxxxxxxxx>

Scale the blanking packet sizes to match the ratio between HS clock
and DPI interface clock. The controller seems to do internal scaling
to the number of active lanes, so we don't take those into account.

Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
Tested-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Tested-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index e0a402a85787..2be3b58624c3 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -874,17 +874,29 @@ static void samsung_dsim_set_display_mode(struct samsung_dsim *dsi)
 	u32 reg;
 
 	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO) {
+		int byte_clk_khz = dsi->burst_clk_rate / 1000 / 8;
+		int hfp = (m->hsync_start - m->hdisplay) * byte_clk_khz / m->clock;
+		int hbp = (m->htotal - m->hsync_end) * byte_clk_khz / m->clock;
+		int hsa = (m->hsync_end - m->hsync_start) * byte_clk_khz / m->clock;
+
+		/* remove packet overhead when possible */
+		hfp = max(hfp - 6, 0);
+		hbp = max(hbp - 6, 0);
+		hsa = max(hsa - 6, 0);
+
+		dev_dbg(dsi->dev, "calculated hfp: %u, hbp: %u, hsa: %u",
+			hfp, hbp, hsa);
+
 		reg = DSIM_CMD_ALLOW(0xf)
 			| DSIM_STABLE_VFP(m->vsync_start - m->vdisplay)
 			| DSIM_MAIN_VBP(m->vtotal - m->vsync_end);
 		samsung_dsim_write(dsi, DSIM_MVPORCH_REG, reg);
 
-		reg = DSIM_MAIN_HFP(m->hsync_start - m->hdisplay)
-			| DSIM_MAIN_HBP(m->htotal - m->hsync_end);
+		reg = DSIM_MAIN_HFP(hfp) | DSIM_MAIN_HBP(hbp);
 		samsung_dsim_write(dsi, DSIM_MHPORCH_REG, reg);
 
 		reg = DSIM_MAIN_VSA(m->vsync_end - m->vsync_start)
-			| DSIM_MAIN_HSA(m->hsync_end - m->hsync_start);
+			| DSIM_MAIN_HSA(hsa);
 		samsung_dsim_write(dsi, DSIM_MSYNC_REG, reg);
 	}
 	reg =  DSIM_MAIN_HRESOL(m->hdisplay, num_bits_resol) |
-- 
2.39.2




[Index of Archives]     [Linux DRI Users]     [Linux Intel Graphics]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux