diff mbox

[v3,14/21] drm/sun4i: tcon: multiply the vtotal when not in interlace

Message ID a8d8a93ddbac69e5dddd9c89a147f8cf2ad043a4.1495006350.git-series.maxime.ripard@free-electrons.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Maxime Ripard May 17, 2017, 7:40 a.m. UTC
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@free-electrons.com>
---
 drivers/gpu/drm/sun4i/sun4i_tcon.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

Comments

Chen-Yu Tsai May 17, 2017, 9:50 a.m. UTC | #1
On Wed, May 17, 2017 at 3:40 PM, Maxime Ripard
<maxime.ripard@free-electrons.com> 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@free-electrons.com>
> ---
>  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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Maxime Ripard May 18, 2017, 7:51 a.m. UTC | #2
On Wed, May 17, 2017 at 05:50:45PM +0800, Chen-Yu Tsai wrote:
> On Wed, May 17, 2017 at 3:40 PM, Maxime Ripard
> <maxime.ripard@free-electrons.com> 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@free-electrons.com>
> > ---
> >  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.

Gaah, you're right, this was obviously meant for the channel 1.. I'll
resend.

Maxime
diff mbox

Patch

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);
 	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 */