On Wed, May 17, 2017 at 3:40 PM, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> 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 | 25 +++++++++++++++++++++----
> 1 file changed, 21 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> index 62e254aedb57..a0f9a8a516c7 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> @@ -153,7 +153,7 @@ static int sun4i_tcon_get_clk_delay(struct drm_display_mode *mode,
> void sun4i_tcon0_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 = 0;
>
> @@ -192,9 +192,26 @@ void sun4i_tcon0_mode_set(struct sun4i_tcon *tcon,
> DRM_DEBUG_DRIVER("Setting vertical total %d, backporch %d\n",
> 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_TCON0_BASIC2_REG,
> - SUN4I_TCON0_BASIC2_V_TOTAL(mode->crtc_vtotal * 2) |
> + SUN4I_TCON0_BASIC2_V_TOTAL(vtotal) |
> SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));
>
> /* Set Hsync and Vsync length */
> @@ -279,9 +296,9 @@ void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon,
> /* 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);
You should duplicate the logic from channel 0 to channel 1.
In fact, interlaced modes happen predominantly on channel 1,
for composite and HDMI modes.
ChenYu
> regmap_write(tcon->regs, SUN4I_TCON1_BASIC4_REG,
> - SUN4I_TCON1_BASIC4_V_TOTAL(mode->vtotal) |
> + SUN4I_TCON1_BASIC4_V_TOTAL(mode->crtc_vtotal * 2) |
> SUN4I_TCON1_BASIC4_V_BACKPORCH(bp));
>
> /* Set Hsync and Vsync length */
> --
> git-series 0.9.1
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