It appears that the total vertical resolution needs to be doubled when
we're not in interlaced. Make sure that is the case.
Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/sun4i/sun4i_tcon.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 61e1de77831d..d9791292553e 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -229,7 +229,7 @@ EXPORT_SYMBOL(sun4i_tcon0_mode_set);
void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon,
struct drm_display_mode *mode)
{
- unsigned int bp, hsync, vsync;
+ unsigned int bp, hsync, vsync, vtotal;
u8 clk_delay;
u32 val;
@@ -276,12 +276,30 @@ void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon,
SUN4I_TCON1_BASIC3_H_TOTAL(mode->crtc_htotal) |
SUN4I_TCON1_BASIC3_H_BACKPORCH(bp));
- /* Set vertical display timings */
bp = mode->crtc_vtotal - mode->crtc_vsync_start;
DRM_DEBUG_DRIVER("Setting vertical total %d, backporch %d\n",
- mode->vtotal, bp);
+ mode->crtc_vtotal, bp);
+
+ /*
+ * The vertical resolution needs to be doubled in all
+ * cases. We could use crtc_vtotal and always multiply by two,
+ * but that leads to a rounding error in interlace when vtotal
+ * is odd.
+ *
+ * This happens with TV's PAL for example, where vtotal will
+ * be 625, crtc_vtotal 312, and thus crtc_vtotal * 2 will be
+ * 624, which apparently confuses the hardware.
+ *
+ * To work around this, we will always use vtotal, and
+ * multiply by two only if we're not in interlace.
+ */
+ vtotal = mode->vtotal;
+ if (!(mode->flags & DRM_MODE_FLAG_INTERLACE))
+ vtotal = vtotal * 2;
+
+ /* Set vertical display timings */
regmap_write(tcon->regs, SUN4I_TCON1_BASIC4_REG,
- SUN4I_TCON1_BASIC4_V_TOTAL(mode->vtotal) |
+ SUN4I_TCON1_BASIC4_V_TOTAL(vtotal) |
SUN4I_TCON1_BASIC4_V_BACKPORCH(bp));
/* Set Hsync and Vsync length */
--
git-series 0.9.1
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