diff mbox series

[v5,19/22] drm/vc4: vec: Check for VEC output constraints

Message ID 20220728-rpi-analog-tv-properties-v5-19-d841cc64fe4b@cerno.tech (mailing list archive)
State New, archived
Headers show
Series drm: Analog TV Improvements | expand

Commit Message

Maxime Ripard Oct. 13, 2022, 1:19 p.m. UTC
From: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>

The VEC can accept pretty much any relatively reasonable mode, but still
has a bunch of constraints to meet.

Let's create an atomic_check() implementation that will make sure we
don't end up accepting a non-functional mode.

Acked-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_vec.c | 48 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

Comments

Mateusz Kwiatkowski Oct. 16, 2022, 6:12 p.m. UTC | #1
Hi Maxime,

W dniu 13.10.2022 o 15:19, Maxime Ripard pisze:
> From: Mateusz Kwiatkowski > > The VEC can accept pretty much any relatively reasonable mode, but still > has a bunch of constraints to meet. > > Let's create an atomic_check() implementation that will make sure we > don't end up accepting a non-functional mode. > > Acked-by: Noralf Trønnes > Signed-off-by: Mateusz Kwiatkowski > Signed-off-by: Maxime Ripard > --- > drivers/gpu/drm/vc4/vc4_vec.c | 48 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 48 insertions(+) > > diff --git a/drivers/gpu/drm/vc4/vc4_vec.c b/drivers/gpu/drm/vc4/vc4_vec.c > index 90e375a8a8f9..1fcb7baf874e 100644 > --- a/drivers/gpu/drm/vc4/vc4_vec.c > +++ b/drivers/gpu/drm/vc4/vc4_vec.c > @@ -453,6 +453,7 @@ static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder, > struct drm_crtc_state *crtc_state, > struct drm_connector_state *conn_state) > { > + const struct drm_display_mode *mode = &crtc_state->adjusted_mode; > const struct vc4_vec_tv_mode *vec_mode; > > vec_mode =
&vc4_vec_tv_modes[conn_state->tv.legacy_mode]; > @@ -461,6 +462,53 @@ static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder, > !drm_mode_equal(vec_mode->mode, &crtc_state->adjusted_mode)) > return -EINVAL; > > + if (mode->crtc_hdisplay % 4) > + return -EINVAL; > + > + if (!(mode->crtc_hsync_end - mode->crtc_hsync_start)) > + return -EINVAL; > + > + switch (mode->vtotal) { > + case 525: > + if (mode->crtc_vtotal > 262) > + return -EINVAL; > + > + if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 253) > + return -EINVAL; > + > + if (!(mode->crtc_vsync_start - mode->crtc_vdisplay)) > + return -EINVAL; > + > + if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3) > + return -EINVAL; > + > + if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 4) > + return -EINVAL; > + > + break; > + > + case 625: > + if (mode->crtc_vtotal > 312) > + return -EINVAL; > + > + if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 305) > + return -EINVAL; > + > + if
(!(mode->crtc_vsync_start - mode->crtc_vdisplay)) > + return -EINVAL; > + > + if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3) > + return -EINVAL; > + > + if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 2) > + return -EINVAL; > + > + break; > + > + default: > + return -EINVAL; > + } > + > return 0; > } In my original version of this function (https://github.com/raspberrypi/linux/pull/4406/files) the switch is over reference_mode->vtotal, not mode->vtotal. This was intended to explicitly allow a different value of mode->vtotal, to support non-standard modes, such as "fake" 525 lines with SECAM encoding, or the progressive modes. You're switching over mode->vtotal, which makes specifying those impossible. I don't think we should limit the users like that. We're removing reference_mode in patch 20/22, so adding a switch over reference_mode->vtotal is probably not a good idea -- in that case I'd switch over mode->htotal instead: 858 for "NTSC" and 864 for "PAL". This
may seem a bit weird, but any other value of htotal causes the VEC to output garbage anyway. Best regards, Mateusz Kwiatkowski
Mateusz Kwiatkowski Oct. 16, 2022, 6:16 p.m. UTC | #2
Hi Maxime,

Sorry about the mess that happened to the previous message. I hope this one
will be delivered more cleanly.

W dniu 13.10.2022 o 15:19, Maxime Ripard pisze:
> From: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
>
> The VEC can accept pretty much any relatively reasonable mode, but still
> has a bunch of constraints to meet.
>
> Let's create an atomic_check() implementation that will make sure we
> don't end up accepting a non-functional mode.
>
> Acked-by: Noralf Trønnes <noralf@tronnes.org>
> Signed-off-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> ---
>  drivers/gpu/drm/vc4/vc4_vec.c | 48 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_vec.c b/drivers/gpu/drm/vc4/vc4_vec.c
> index 90e375a8a8f9..1fcb7baf874e 100644
> --- a/drivers/gpu/drm/vc4/vc4_vec.c
> +++ b/drivers/gpu/drm/vc4/vc4_vec.c
> @@ -453,6 +453,7 @@ static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder,
>                      struct drm_crtc_state *crtc_state,
>                      struct drm_connector_state *conn_state)
>  {
> +    const struct drm_display_mode *mode = &crtc_state->adjusted_mode;
>      const struct vc4_vec_tv_mode *vec_mode;
>  
>      vec_mode = &vc4_vec_tv_modes[conn_state->tv.legacy_mode];
> @@ -461,6 +462,53 @@ static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder,
>          !drm_mode_equal(vec_mode->mode, &crtc_state->adjusted_mode))
>          return -EINVAL;
>  
> +    if (mode->crtc_hdisplay % 4)
> +        return -EINVAL;
> +
> +    if (!(mode->crtc_hsync_end - mode->crtc_hsync_start))
> +        return -EINVAL;
> +
> +    switch (mode->vtotal) {
> +    case 525:
> +        if (mode->crtc_vtotal > 262)
> +            return -EINVAL;
> +
> +        if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 253)
> +            return -EINVAL;
> +
> +        if (!(mode->crtc_vsync_start - mode->crtc_vdisplay))
> +            return -EINVAL;
> +
> +        if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3)
> +            return -EINVAL;
> +
> +        if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 4)
> +            return -EINVAL;
> +
> +        break;
> +
> +    case 625:
> +        if (mode->crtc_vtotal > 312)
> +            return -EINVAL;
> +
> +        if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 305)
> +            return -EINVAL;
> +
> +        if (!(mode->crtc_vsync_start - mode->crtc_vdisplay))
> +            return -EINVAL;
> +
> +        if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3)
> +            return -EINVAL;
> +
> +        if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 2)
> +            return -EINVAL;
> +
> +        break;
> +
> +    default:
> +        return -EINVAL;
> +    }
> +
>      return 0;
>  }
>  
>

In my original version of this function
(https://github.com/raspberrypi/linux/pull/4406/files) the switch is over
reference_mode->vtotal, not mode->vtotal. This was intended to explicitly allow
a different value of mode->vtotal, to support non-standard modes, such as "fake"
525 lines with SECAM encoding, or the progressive modes.

You're switching over mode->vtotal, which makes specifying those impossible.
I don't think we should limit the users like that.

We're removing reference_mode in patch 20/22, so adding a switch over
reference_mode->vtotal is probably not a good idea -- in that case I'd switch
over mode->htotal instead: 858 for "NTSC" and 864 for "PAL". This may seem a bit
weird, but any other value of htotal causes the VEC to output garbage anyway.

Best regards,
Mateusz Kwiatkowski
Maxime Ripard Oct. 18, 2022, 8:27 a.m. UTC | #3
Hi,

On Sun, Oct 16, 2022 at 08:16:32PM +0200, Mateusz Kwiatkowski wrote:
> W dniu 13.10.2022 o 15:19, Maxime Ripard pisze:
> > From: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
> >
> > The VEC can accept pretty much any relatively reasonable mode, but still
> > has a bunch of constraints to meet.
> >
> > Let's create an atomic_check() implementation that will make sure we
> > don't end up accepting a non-functional mode.
> >
> > Acked-by: Noralf Trønnes <noralf@tronnes.org>
> > Signed-off-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
> > Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> > ---
> >  drivers/gpu/drm/vc4/vc4_vec.c | 48 +++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 48 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/vc4/vc4_vec.c b/drivers/gpu/drm/vc4/vc4_vec.c
> > index 90e375a8a8f9..1fcb7baf874e 100644
> > --- a/drivers/gpu/drm/vc4/vc4_vec.c
> > +++ b/drivers/gpu/drm/vc4/vc4_vec.c
> > @@ -453,6 +453,7 @@ static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder,
> >                      struct drm_crtc_state *crtc_state,
> >                      struct drm_connector_state *conn_state)
> >  {
> > +    const struct drm_display_mode *mode = &crtc_state->adjusted_mode;
> >      const struct vc4_vec_tv_mode *vec_mode;
> >  
> >      vec_mode = &vc4_vec_tv_modes[conn_state->tv.legacy_mode];
> > @@ -461,6 +462,53 @@ static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder,
> >          !drm_mode_equal(vec_mode->mode, &crtc_state->adjusted_mode))
> >          return -EINVAL;
> >  
> > +    if (mode->crtc_hdisplay % 4)
> > +        return -EINVAL;
> > +
> > +    if (!(mode->crtc_hsync_end - mode->crtc_hsync_start))
> > +        return -EINVAL;
> > +
> > +    switch (mode->vtotal) {
> > +    case 525:
> > +        if (mode->crtc_vtotal > 262)
> > +            return -EINVAL;
> > +
> > +        if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 253)
> > +            return -EINVAL;
> > +
> > +        if (!(mode->crtc_vsync_start - mode->crtc_vdisplay))
> > +            return -EINVAL;
> > +
> > +        if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3)
> > +            return -EINVAL;
> > +
> > +        if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 4)
> > +            return -EINVAL;
> > +
> > +        break;
> > +
> > +    case 625:
> > +        if (mode->crtc_vtotal > 312)
> > +            return -EINVAL;
> > +
> > +        if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 305)
> > +            return -EINVAL;
> > +
> > +        if (!(mode->crtc_vsync_start - mode->crtc_vdisplay))
> > +            return -EINVAL;
> > +
> > +        if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3)
> > +            return -EINVAL;
> > +
> > +        if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 2)
> > +            return -EINVAL;
> > +
> > +        break;
> > +
> > +    default:
> > +        return -EINVAL;
> > +    }
> > +
> >      return 0;
> >  }
> >  
> >
> 
> In my original version of this function
> (https://github.com/raspberrypi/linux/pull/4406/files) the switch is over
> reference_mode->vtotal, not mode->vtotal. This was intended to explicitly allow
> a different value of mode->vtotal, to support non-standard modes, such as "fake"
> 525 lines with SECAM encoding, or the progressive modes.
>
> You're switching over mode->vtotal, which makes specifying those impossible.
> I don't think we should limit the users like that.
>
> We're removing reference_mode in patch 20/22, so adding a switch over
> reference_mode->vtotal is probably not a good idea in that case I'd switch
> over mode->htotal instead: 858 for "NTSC" and 864 for "PAL". This may seem a bit
> weird, but any other value of htotal causes the VEC to output garbage anyway.

Ack, I'll change it.

If it ever causes an issue, we can always switch back to a reference
mode anyway. We'd just have to call drm_mode_analog_tv at each
atomic_check so I'd rather avoid the overhead if we can

Maxime
diff mbox series

Patch

diff --git a/drivers/gpu/drm/vc4/vc4_vec.c b/drivers/gpu/drm/vc4/vc4_vec.c
index 90e375a8a8f9..1fcb7baf874e 100644
--- a/drivers/gpu/drm/vc4/vc4_vec.c
+++ b/drivers/gpu/drm/vc4/vc4_vec.c
@@ -453,6 +453,7 @@  static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder,
 					struct drm_crtc_state *crtc_state,
 					struct drm_connector_state *conn_state)
 {
+	const struct drm_display_mode *mode = &crtc_state->adjusted_mode;
 	const struct vc4_vec_tv_mode *vec_mode;
 
 	vec_mode = &vc4_vec_tv_modes[conn_state->tv.legacy_mode];
@@ -461,6 +462,53 @@  static int vc4_vec_encoder_atomic_check(struct drm_encoder *encoder,
 	    !drm_mode_equal(vec_mode->mode, &crtc_state->adjusted_mode))
 		return -EINVAL;
 
+	if (mode->crtc_hdisplay % 4)
+		return -EINVAL;
+
+	if (!(mode->crtc_hsync_end - mode->crtc_hsync_start))
+		return -EINVAL;
+
+	switch (mode->vtotal) {
+	case 525:
+		if (mode->crtc_vtotal > 262)
+			return -EINVAL;
+
+		if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 253)
+			return -EINVAL;
+
+		if (!(mode->crtc_vsync_start - mode->crtc_vdisplay))
+			return -EINVAL;
+
+		if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3)
+			return -EINVAL;
+
+		if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 4)
+			return -EINVAL;
+
+		break;
+
+	case 625:
+		if (mode->crtc_vtotal > 312)
+			return -EINVAL;
+
+		if (mode->crtc_vdisplay < 1 || mode->crtc_vdisplay > 305)
+			return -EINVAL;
+
+		if (!(mode->crtc_vsync_start - mode->crtc_vdisplay))
+			return -EINVAL;
+
+		if ((mode->crtc_vsync_end - mode->crtc_vsync_start) != 3)
+			return -EINVAL;
+
+		if ((mode->crtc_vtotal - mode->crtc_vsync_end) < 2)
+			return -EINVAL;
+
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
 	return 0;
 }