According to the BSP source code, when calculating the magic DRQ value
outside burst mode, a formula of "lcd_ht - lcd_x - lcd_hbp", which is
interpreted as right margin (HFP value). However, currently the
sun6i_mipi_dsi driver code calculates it wrongly as HFP + sync length,
which lead to timing error.
Fix the DRQ calculation by change it to use HFP.
Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
---
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index c86e11631ebc..2d3e822a7739 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -436,9 +436,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
SUN6I_DSI_BURST_LINE_SYNC_POINT(SUN6I_DSI_SYNC_POINT));
val = SUN6I_DSI_TCON_DRQ_ENABLE_MODE;
- } else if ((mode->hsync_end - mode->hdisplay) > 20) {
+ } else if ((mode->hsync_start - mode->hdisplay) > 20) {
/* Maaaaaagic */
- u16 drq = (mode->hsync_end - mode->hdisplay) - 20;
+ u16 drq = (mode->hsync_start - mode->hdisplay) - 20;
drq *= mipi_dsi_pixel_format_to_bpp(device->format);
drq /= 32;
--
2.21.0
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