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* [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
@ 2019-01-10 15:10 Peter Rosin
  2019-01-10 15:10 ` [PATCH 1/4] drm/atmel-hlcdc: rotate planes counterclockwise Peter Rosin
                   ` (5 more replies)
  0 siblings, 6 replies; 21+ messages in thread
From: Peter Rosin @ 2019-01-10 15:10 UTC (permalink / raw)
  To: linux-kernel
  Cc: Alexandre Belloni, David Airlie, dri-devel, Boris Brezillon,
	Peter Rosin, linux-arm-kernel

Hi!

I found an unfortunate issue while recoding plane handling to use
drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
which is not correct. I simply fixed it (patch 1/4), but maybe that
will cause regressions for unsuspecting users who simply assumed
that the clockwise rotation was correct? I don't know what to do
about that? Adding an option to get the old broken behavior seems
useless, wouldn't it be just as easy to just fix whatever app to
rotate the other way instead of adding an option somewhere?

I have only tested this series on sama5d3, but I did check the docs
for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
and sam9x35) supported by the driver (relevant to patch 4/4).

Cheers,
Peter

Peter Rosin (4):
  drm/atmel-hlcdc: rotate planes counterclockwise
  drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
  drm/atmel-hlcdc: fix clipping of planes
  drm/atmel-hlcdc: do not immediately disable planes, wait for next
    frame

 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 179 +++++++++---------------
 1 file changed, 67 insertions(+), 112 deletions(-)

-- 
2.11.0


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^ permalink raw reply	[flat|nested] 21+ messages in thread

* [PATCH 1/4] drm/atmel-hlcdc: rotate planes counterclockwise
  2019-01-10 15:10 [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Peter Rosin
@ 2019-01-10 15:10 ` Peter Rosin
  2019-01-10 15:10 ` [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated Peter Rosin
                   ` (4 subsequent siblings)
  5 siblings, 0 replies; 21+ messages in thread
From: Peter Rosin @ 2019-01-10 15:10 UTC (permalink / raw)
  To: linux-kernel
  Cc: Alexandre Belloni, David Airlie, dri-devel, Boris Brezillon,
	Peter Rosin, linux-arm-kernel

Ouch, the driver rotates planes clockwise, which is simply not correct.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 30 ++++++++++++-------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
index 47e0992f3908..ea8fc0deb814 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
@@ -691,13 +691,14 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 
 		switch (state->base.rotation & DRM_MODE_ROTATE_MASK) {
 		case DRM_MODE_ROTATE_90:
-			offset = ((y_offset + state->src_y + patched_src_w - 1) /
-				  ydiv) * fb->pitches[i];
-			offset += ((x_offset + state->src_x) / xdiv) *
-				  state->bpp[i];
-			state->xstride[i] = ((patched_src_w - 1) / ydiv) *
-					  fb->pitches[i];
-			state->pstride[i] = -fb->pitches[i] - state->bpp[i];
+			offset = ((y_offset + state->src_y) / ydiv) *
+				 fb->pitches[i];
+			offset += ((x_offset + state->src_x + patched_src_h - 1) /
+				   xdiv) * state->bpp[i];
+			state->xstride[i] = -(((patched_src_w - 1) / ydiv) *
+					    fb->pitches[i]) -
+					  (2 * state->bpp[i]);
+			state->pstride[i] = fb->pitches[i] - state->bpp[i];
 			break;
 		case DRM_MODE_ROTATE_180:
 			offset = ((y_offset + state->src_y + patched_src_h - 1) /
@@ -709,14 +710,13 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 			state->pstride[i] = -2 * state->bpp[i];
 			break;
 		case DRM_MODE_ROTATE_270:
-			offset = ((y_offset + state->src_y) / ydiv) *
-				 fb->pitches[i];
-			offset += ((x_offset + state->src_x + patched_src_h - 1) /
-				   xdiv) * state->bpp[i];
-			state->xstride[i] = -(((patched_src_w - 1) / ydiv) *
-					    fb->pitches[i]) -
-					  (2 * state->bpp[i]);
-			state->pstride[i] = fb->pitches[i] - state->bpp[i];
+			offset = ((y_offset + state->src_y + patched_src_w - 1) /
+				  ydiv) * fb->pitches[i];
+			offset += ((x_offset + state->src_x) / xdiv) *
+				  state->bpp[i];
+			state->xstride[i] = ((patched_src_w - 1) / ydiv) *
+					  fb->pitches[i];
+			state->pstride[i] = -fb->pitches[i] - state->bpp[i];
 			break;
 		case DRM_MODE_ROTATE_0:
 		default:
-- 
2.11.0


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^ permalink raw reply	[flat|nested] 21+ messages in thread

* [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
  2019-01-10 15:10 [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Peter Rosin
  2019-01-10 15:10 ` [PATCH 1/4] drm/atmel-hlcdc: rotate planes counterclockwise Peter Rosin
@ 2019-01-10 15:10 ` Peter Rosin
  2019-01-10 17:48   ` Boris Brezillon
  2019-01-10 15:10 ` [PATCH 3/4] drm/atmel-hlcdc: fix clipping of planes Peter Rosin
                   ` (3 subsequent siblings)
  5 siblings, 1 reply; 21+ messages in thread
From: Peter Rosin @ 2019-01-10 15:10 UTC (permalink / raw)
  To: linux-kernel
  Cc: Alexandre Belloni, David Airlie, dri-devel, Boris Brezillon,
	Peter Rosin, linux-arm-kernel

The destination crtc rectangle is independent of source plane rotation.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
index ea8fc0deb814..d6f93f029020 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
@@ -642,9 +642,6 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 	 * Swap width and size in case of 90 or 270 degrees rotation
 	 */
 	if (drm_rotation_90_or_270(state->base.rotation)) {
-		tmp = state->crtc_w;
-		state->crtc_w = state->crtc_h;
-		state->crtc_h = tmp;
 		tmp = state->src_w;
 		state->src_w = state->src_h;
 		state->src_h = tmp;
-- 
2.11.0


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^ permalink raw reply	[flat|nested] 21+ messages in thread

* [PATCH 3/4] drm/atmel-hlcdc: fix clipping of planes
  2019-01-10 15:10 [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Peter Rosin
  2019-01-10 15:10 ` [PATCH 1/4] drm/atmel-hlcdc: rotate planes counterclockwise Peter Rosin
  2019-01-10 15:10 ` [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated Peter Rosin
@ 2019-01-10 15:10 ` Peter Rosin
  2019-01-10 15:10 ` [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame Peter Rosin
                   ` (2 subsequent siblings)
  5 siblings, 0 replies; 21+ messages in thread
From: Peter Rosin @ 2019-01-10 15:10 UTC (permalink / raw)
  To: linux-kernel
  Cc: Alexandre Belloni, David Airlie, dri-devel, Boris Brezillon,
	Peter Rosin, linux-arm-kernel

With the help from drm_atomic_helper_check_plane_state function, clipping
now handles planes to be partially or totally off-screen. The plane is
disabled if it is not visible.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 162 +++++++++---------------
 1 file changed, 61 insertions(+), 101 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
index d6f93f029020..05519e8c6586 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
@@ -548,7 +548,8 @@ atmel_hlcdc_plane_prepare_disc_area(struct drm_crtc_state *c_state)
 
 		ovl_state = drm_plane_state_to_atmel_hlcdc_plane_state(ovl_s);
 
-		if (!ovl_s->fb ||
+		if (!ovl_s->visible ||
+		    !ovl_s->fb ||
 		    ovl_s->fb->format->has_alpha ||
 		    ovl_s->alpha != DRM_BLEND_ALPHA_OPAQUE)
 			continue;
@@ -600,15 +601,10 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 	struct drm_framebuffer *fb = state->base.fb;
 	const struct drm_display_mode *mode;
 	struct drm_crtc_state *crtc_state;
-	unsigned int patched_crtc_w;
-	unsigned int patched_crtc_h;
-	unsigned int patched_src_w;
-	unsigned int patched_src_h;
 	unsigned int tmp;
-	int x_offset = 0;
-	int y_offset = 0;
 	int hsub = 1;
 	int vsub = 1;
+	int ret;
 	int i;
 
 	if (!state->base.crtc || !fb)
@@ -617,14 +613,21 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 	crtc_state = drm_atomic_get_existing_crtc_state(s->state, s->crtc);
 	mode = &crtc_state->adjusted_mode;
 
-	state->src_x = s->src_x;
-	state->src_y = s->src_y;
-	state->src_h = s->src_h;
-	state->src_w = s->src_w;
-	state->crtc_x = s->crtc_x;
-	state->crtc_y = s->crtc_y;
-	state->crtc_h = s->crtc_h;
-	state->crtc_w = s->crtc_w;
+	ret = drm_atomic_helper_check_plane_state(s, crtc_state,
+						  (1 << 16) / 2048,
+						  INT_MAX, true, true);
+	if (ret || !s->visible)
+		return ret;
+
+	state->src_x = s->src.x1;
+	state->src_y = s->src.y1;
+	state->src_w = drm_rect_width(&s->src);
+	state->src_h = drm_rect_height(&s->src);
+	state->crtc_x = s->dst.x1;
+	state->crtc_y = s->dst.y1;
+	state->crtc_w = drm_rect_width(&s->dst);
+	state->crtc_h = drm_rect_height(&s->dst);
+
 	if ((state->src_x | state->src_y | state->src_w | state->src_h) &
 	    SUBPIXEL_MASK)
 		return -EINVAL;
@@ -638,42 +641,6 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 	if (state->nplanes > ATMEL_HLCDC_LAYER_MAX_PLANES)
 		return -EINVAL;
 
-	/*
-	 * Swap width and size in case of 90 or 270 degrees rotation
-	 */
-	if (drm_rotation_90_or_270(state->base.rotation)) {
-		tmp = state->src_w;
-		state->src_w = state->src_h;
-		state->src_h = tmp;
-	}
-
-	if (state->crtc_x + state->crtc_w > mode->hdisplay)
-		patched_crtc_w = mode->hdisplay - state->crtc_x;
-	else
-		patched_crtc_w = state->crtc_w;
-
-	if (state->crtc_x < 0) {
-		patched_crtc_w += state->crtc_x;
-		x_offset = -state->crtc_x;
-		state->crtc_x = 0;
-	}
-
-	if (state->crtc_y + state->crtc_h > mode->vdisplay)
-		patched_crtc_h = mode->vdisplay - state->crtc_y;
-	else
-		patched_crtc_h = state->crtc_h;
-
-	if (state->crtc_y < 0) {
-		patched_crtc_h += state->crtc_y;
-		y_offset = -state->crtc_y;
-		state->crtc_y = 0;
-	}
-
-	patched_src_w = DIV_ROUND_CLOSEST(patched_crtc_w * state->src_w,
-					  state->crtc_w);
-	patched_src_h = DIV_ROUND_CLOSEST(patched_crtc_h * state->src_h,
-					  state->crtc_h);
-
 	hsub = drm_format_horz_chroma_subsampling(fb->format->format);
 	vsub = drm_format_vert_chroma_subsampling(fb->format->format);
 
@@ -688,41 +655,38 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 
 		switch (state->base.rotation & DRM_MODE_ROTATE_MASK) {
 		case DRM_MODE_ROTATE_90:
-			offset = ((y_offset + state->src_y) / ydiv) *
+			offset = (state->src_y / ydiv) *
 				 fb->pitches[i];
-			offset += ((x_offset + state->src_x + patched_src_h - 1) /
+			offset += ((state->src_x + state->src_w - 1) /
 				   xdiv) * state->bpp[i];
-			state->xstride[i] = -(((patched_src_w - 1) / ydiv) *
+			state->xstride[i] = -(((state->src_h - 1) / ydiv) *
 					    fb->pitches[i]) -
 					  (2 * state->bpp[i]);
 			state->pstride[i] = fb->pitches[i] - state->bpp[i];
 			break;
 		case DRM_MODE_ROTATE_180:
-			offset = ((y_offset + state->src_y + patched_src_h - 1) /
+			offset = ((state->src_y + state->src_h - 1) /
 				  ydiv) * fb->pitches[i];
-			offset += ((x_offset + state->src_x + patched_src_w - 1) /
+			offset += ((state->src_x + state->src_w - 1) /
 				   xdiv) * state->bpp[i];
-			state->xstride[i] = ((((patched_src_w - 1) / xdiv) - 1) *
+			state->xstride[i] = ((((state->src_w - 1) / xdiv) - 1) *
 					   state->bpp[i]) - fb->pitches[i];
 			state->pstride[i] = -2 * state->bpp[i];
 			break;
 		case DRM_MODE_ROTATE_270:
-			offset = ((y_offset + state->src_y + patched_src_w - 1) /
+			offset = ((state->src_y + state->src_h - 1) /
 				  ydiv) * fb->pitches[i];
-			offset += ((x_offset + state->src_x) / xdiv) *
-				  state->bpp[i];
-			state->xstride[i] = ((patched_src_w - 1) / ydiv) *
+			offset += (state->src_x / xdiv) * state->bpp[i];
+			state->xstride[i] = ((state->src_h - 1) / ydiv) *
 					  fb->pitches[i];
 			state->pstride[i] = -fb->pitches[i] - state->bpp[i];
 			break;
 		case DRM_MODE_ROTATE_0:
 		default:
-			offset = ((y_offset + state->src_y) / ydiv) *
-				 fb->pitches[i];
-			offset += ((x_offset + state->src_x) / xdiv) *
-				  state->bpp[i];
+			offset = (state->src_y / ydiv) * fb->pitches[i];
+			offset += (state->src_x / xdiv) * state->bpp[i];
 			state->xstride[i] = fb->pitches[i] -
-					  ((patched_src_w / xdiv) *
+					  ((state->src_w / xdiv) *
 					   state->bpp[i]);
 			state->pstride[i] = 0;
 			break;
@@ -731,35 +695,45 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
 		state->offsets[i] = offset + fb->offsets[i];
 	}
 
-	state->src_w = patched_src_w;
-	state->src_h = patched_src_h;
-	state->crtc_w = patched_crtc_w;
-	state->crtc_h = patched_crtc_h;
+	/*
+	 * Swap width and size in case of 90 or 270 degrees rotation
+	 */
+	if (drm_rotation_90_or_270(state->base.rotation)) {
+		tmp = state->src_w;
+		state->src_w = state->src_h;
+		state->src_h = tmp;
+	}
 
 	if (!desc->layout.size &&
 	    (mode->hdisplay != state->crtc_w ||
 	     mode->vdisplay != state->crtc_h))
 		return -EINVAL;
 
-	if (desc->max_height && state->crtc_h > desc->max_height)
-		return -EINVAL;
-
-	if (desc->max_width && state->crtc_w > desc->max_width)
-		return -EINVAL;
-
 	if ((state->crtc_h != state->src_h || state->crtc_w != state->src_w) &&
 	    (!desc->layout.memsize ||
 	     state->base.fb->format->has_alpha))
 		return -EINVAL;
 
-	if (state->crtc_x < 0 || state->crtc_y < 0)
-		return -EINVAL;
+	return 0;
+}
 
-	if (state->crtc_w + state->crtc_x > mode->hdisplay ||
-	    state->crtc_h + state->crtc_y > mode->vdisplay)
-		return -EINVAL;
+static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
+					     struct drm_plane_state *old_state)
+{
+	struct atmel_hlcdc_plane *plane = drm_plane_to_atmel_hlcdc_plane(p);
 
-	return 0;
+	/* Disable interrupts */
+	atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_IDR,
+				    0xffffffff);
+
+	/* Disable the layer */
+	atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHDR,
+				    ATMEL_HLCDC_LAYER_RST |
+				    ATMEL_HLCDC_LAYER_A2Q |
+				    ATMEL_HLCDC_LAYER_UPDATE);
+
+	/* Clear all pending interrupts */
+	atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);
 }
 
 static void atmel_hlcdc_plane_atomic_update(struct drm_plane *p,
@@ -773,6 +747,11 @@ static void atmel_hlcdc_plane_atomic_update(struct drm_plane *p,
 	if (!p->state->crtc || !p->state->fb)
 		return;
 
+	if (!state->base.visible) {
+		atmel_hlcdc_plane_atomic_disable(p, old_s);
+		return;
+	}
+
 	atmel_hlcdc_plane_update_pos_and_size(plane, state);
 	atmel_hlcdc_plane_update_general_settings(plane, state);
 	atmel_hlcdc_plane_update_format(plane, state);
@@ -794,25 +773,6 @@ static void atmel_hlcdc_plane_atomic_update(struct drm_plane *p,
 			 ATMEL_HLCDC_LAYER_A2Q : ATMEL_HLCDC_LAYER_EN));
 }
 
-static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
-					     struct drm_plane_state *old_state)
-{
-	struct atmel_hlcdc_plane *plane = drm_plane_to_atmel_hlcdc_plane(p);
-
-	/* Disable interrupts */
-	atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_IDR,
-				    0xffffffff);
-
-	/* Disable the layer */
-	atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHDR,
-				    ATMEL_HLCDC_LAYER_RST |
-				    ATMEL_HLCDC_LAYER_A2Q |
-				    ATMEL_HLCDC_LAYER_UPDATE);
-
-	/* Clear all pending interrupts */
-	atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);
-}
-
 static void atmel_hlcdc_plane_destroy(struct drm_plane *p)
 {
 	struct atmel_hlcdc_plane *plane = drm_plane_to_atmel_hlcdc_plane(p);
-- 
2.11.0


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^ permalink raw reply	[flat|nested] 21+ messages in thread

* [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame
  2019-01-10 15:10 [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Peter Rosin
                   ` (2 preceding siblings ...)
  2019-01-10 15:10 ` [PATCH 3/4] drm/atmel-hlcdc: fix clipping of planes Peter Rosin
@ 2019-01-10 15:10 ` Peter Rosin
  2019-01-10 17:29   ` Boris Brezillon
  2019-01-10 17:45 ` [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Boris Brezillon
  2019-01-27  8:27 ` Boris Brezillon
  5 siblings, 1 reply; 21+ messages in thread
From: Peter Rosin @ 2019-01-10 15:10 UTC (permalink / raw)
  To: linux-kernel
  Cc: Alexandre Belloni, David Airlie, dri-devel, Boris Brezillon,
	Peter Rosin, linux-arm-kernel

The A2Q and UPDATE bits have no effect in the channel disable registers.
However, since they are present, assume that the intention is to disable
planes, not immediately as indicated by the RST bit, but on the next
frame shift since that is what A2Q and UPDATE means in the channel enable
registers.

Disabling the plane on the next frame shift is done with the EN bit,
so use that.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
index 05519e8c6586..f2f570642f84 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
@@ -728,9 +728,7 @@ static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
 
 	/* Disable the layer */
 	atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHDR,
-				    ATMEL_HLCDC_LAYER_RST |
-				    ATMEL_HLCDC_LAYER_A2Q |
-				    ATMEL_HLCDC_LAYER_UPDATE);
+				    ATMEL_HLCDC_LAYER_EN);
 
 	/* Clear all pending interrupts */
 	atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);
-- 
2.11.0


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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame
  2019-01-10 15:10 ` [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame Peter Rosin
@ 2019-01-10 17:29   ` Boris Brezillon
  2019-01-10 18:51     ` Peter Rosin
  0 siblings, 1 reply; 21+ messages in thread
From: Boris Brezillon @ 2019-01-10 17:29 UTC (permalink / raw)
  To: Peter Rosin
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On Thu, 10 Jan 2019 15:10:48 +0000
Peter Rosin <peda@axentia.se> wrote:

> The A2Q and UPDATE bits have no effect in the channel disable registers.
> However, since they are present, assume that the intention is to disable
> planes, not immediately as indicated by the RST bit, but on the next
> frame shift since that is what A2Q and UPDATE means in the channel enable
> registers.
> 
> Disabling the plane on the next frame shift is done with the EN bit,
> so use that.

It's been a long time, but I think I had a good reason for forcing a
reset. IIRC, when you don't do that and the CRTC is disabled before the
plane, the EN bit stays around, and next time you queue a plane update,
you'll start with an invalid buf pointer.

> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> index 05519e8c6586..f2f570642f84 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> @@ -728,9 +728,7 @@ static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
>  
>  	/* Disable the layer */
>  	atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHDR,
> -				    ATMEL_HLCDC_LAYER_RST |
> -				    ATMEL_HLCDC_LAYER_A2Q |
> -				    ATMEL_HLCDC_LAYER_UPDATE);
> +				    ATMEL_HLCDC_LAYER_EN);
>  
>  	/* Clear all pending interrupts */
>  	atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);


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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
  2019-01-10 15:10 [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Peter Rosin
                   ` (3 preceding siblings ...)
  2019-01-10 15:10 ` [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame Peter Rosin
@ 2019-01-10 17:45 ` Boris Brezillon
  2019-01-10 20:16   ` Sam Ravnborg
                     ` (2 more replies)
  2019-01-27  8:27 ` Boris Brezillon
  5 siblings, 3 replies; 21+ messages in thread
From: Boris Brezillon @ 2019-01-10 17:45 UTC (permalink / raw)
  To: Peter Rosin
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On Thu, 10 Jan 2019 15:10:28 +0000
Peter Rosin <peda@axentia.se> wrote:

> Hi!
> 
> I found an unfortunate issue while recoding plane handling to use
> drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
> which is not correct. I simply fixed it (patch 1/4), but maybe that
> will cause regressions for unsuspecting users who simply assumed
> that the clockwise rotation was correct? I don't know what to do
> about that? Adding an option to get the old broken behavior seems
> useless, wouldn't it be just as easy to just fix whatever app to
> rotate the other way instead of adding an option somewhere?

Hm, rotation support has been added before the standard rotation
property was created, and at that time I assumed rotation was clockwise
(which apparently was an unwise choice). Anyway, I don't have a
solution for this problem, so I'll let Nicolas decide if it's
acceptable to change the rotation behavior.

> 
> I have only tested this series on sama5d3, but I did check the docs
> for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
> and sam9x35) supported by the driver (relevant to patch 4/4).

Thanks for addressing those problems.

> 
> Cheers,
> Peter
> 
> Peter Rosin (4):
>   drm/atmel-hlcdc: rotate planes counterclockwise
>   drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
>   drm/atmel-hlcdc: fix clipping of planes
>   drm/atmel-hlcdc: do not immediately disable planes, wait for next
>     frame
> 
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 179 +++++++++---------------
>  1 file changed, 67 insertions(+), 112 deletions(-)
> 


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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
  2019-01-10 15:10 ` [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated Peter Rosin
@ 2019-01-10 17:48   ` Boris Brezillon
  2019-01-11 13:29     ` Peter Rosin
  0 siblings, 1 reply; 21+ messages in thread
From: Boris Brezillon @ 2019-01-10 17:48 UTC (permalink / raw)
  To: Peter Rosin
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On Thu, 10 Jan 2019 15:10:39 +0000
Peter Rosin <peda@axentia.se> wrote:

> The destination crtc rectangle is independent of source plane rotation.
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> index ea8fc0deb814..d6f93f029020 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> @@ -642,9 +642,6 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
>  	 * Swap width and size in case of 90 or 270 degrees rotation
>  	 */
>  	if (drm_rotation_90_or_270(state->base.rotation)) {
> -		tmp = state->crtc_w;
> -		state->crtc_w = state->crtc_h;
> -		state->crtc_h = tmp;

Again, I guess I assumed ->crtc_h/w were the width and height before
rotation when I initially added rotation support. This change might
break users too.

>  		tmp = state->src_w;
>  		state->src_w = state->src_h;
>  		state->src_h = tmp;


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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame
  2019-01-10 17:29   ` Boris Brezillon
@ 2019-01-10 18:51     ` Peter Rosin
  2019-01-10 19:25       ` Boris Brezillon
  0 siblings, 1 reply; 21+ messages in thread
From: Peter Rosin @ 2019-01-10 18:51 UTC (permalink / raw)
  To: Boris Brezillon
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On 2019-01-10 18:29, Boris Brezillon wrote:
> On Thu, 10 Jan 2019 15:10:48 +0000
> Peter Rosin <peda@axentia.se> wrote:
> 
>> The A2Q and UPDATE bits have no effect in the channel disable registers.
>> However, since they are present, assume that the intention is to disable
>> planes, not immediately as indicated by the RST bit, but on the next
>> frame shift since that is what A2Q and UPDATE means in the channel enable
>> registers.
>>
>> Disabling the plane on the next frame shift is done with the EN bit,
>> so use that.
> 
> It's been a long time, but I think I had a good reason for forcing a
> reset. IIRC, when you don't do that and the CRTC is disabled before the
> plane, the EN bit stays around, and next time you queue a plane update,
> you'll start with an invalid buf pointer.

It might be possible to clear the EN bit in ...CHDR before enabling the
plane in ...CHER. Or is that too late? But this patch is not overly
important, I just wanted to avoid the resulting "black hole" when the
plane DMA is disabled mid-frame. But disabling planes is probably not
something that happens frequently and will perhaps not be noticed at
all...

Cheers,
Peter

>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
>> ---
>>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 4 +---
>>  1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>> index 05519e8c6586..f2f570642f84 100644
>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>> @@ -728,9 +728,7 @@ static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
>>  
>>  	/* Disable the layer */
>>  	atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHDR,
>> -				    ATMEL_HLCDC_LAYER_RST |
>> -				    ATMEL_HLCDC_LAYER_A2Q |
>> -				    ATMEL_HLCDC_LAYER_UPDATE);
>> +				    ATMEL_HLCDC_LAYER_EN);
>>  
>>  	/* Clear all pending interrupts */
>>  	atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);
> 

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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame
  2019-01-10 18:51     ` Peter Rosin
@ 2019-01-10 19:25       ` Boris Brezillon
  2019-01-11 14:29         ` Peter Rosin
  0 siblings, 1 reply; 21+ messages in thread
From: Boris Brezillon @ 2019-01-10 19:25 UTC (permalink / raw)
  To: Peter Rosin
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On Thu, 10 Jan 2019 18:51:21 +0000
Peter Rosin <peda@axentia.se> wrote:

> On 2019-01-10 18:29, Boris Brezillon wrote:
> > On Thu, 10 Jan 2019 15:10:48 +0000
> > Peter Rosin <peda@axentia.se> wrote:
> >   
> >> The A2Q and UPDATE bits have no effect in the channel disable registers.
> >> However, since they are present, assume that the intention is to disable
> >> planes, not immediately as indicated by the RST bit, but on the next
> >> frame shift since that is what A2Q and UPDATE means in the channel enable
> >> registers.
> >>
> >> Disabling the plane on the next frame shift is done with the EN bit,
> >> so use that.  
> > 
> > It's been a long time, but I think I had a good reason for forcing a
> > reset. IIRC, when you don't do that and the CRTC is disabled before the
> > plane, the EN bit stays around, and next time you queue a plane update,
> > you'll start with an invalid buf pointer.  
> 
> It might be possible to clear the EN bit in ...CHDR before enabling the
> plane in ...CHER. Or is that too late?

I think I tried that, but I'm not sure (BTW, this change was done in
bd4248bb5e8b ("drm: atmel-hlcdc: reset layer A2Q and UPDATE bits when
disabling it")). Anyway, I'm not even sure this is still needed now
that atomic updates have a wait_for_flip_done/vblank() in the commit
path.

> But this patch is not overly
> important, I just wanted to avoid the resulting "black hole" when the
> plane DMA is disabled mid-frame. But disabling planes is probably not
> something that happens frequently and will perhaps not be noticed at
> all...

Okay. Other patches look good to me, I'm just waiting for Nicolas
feedback before applying them.

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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
  2019-01-10 17:45 ` [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Boris Brezillon
@ 2019-01-10 20:16   ` Sam Ravnborg
  2019-01-11  9:16     ` Peter Rosin
  2019-01-10 21:24   ` Peter Rosin
  2019-01-11 14:18   ` Nicolas.Ferre
  2 siblings, 1 reply; 21+ messages in thread
From: Sam Ravnborg @ 2019-01-10 20:16 UTC (permalink / raw)
  To: Boris Brezillon, Peter Rosin
  Cc: Alexandre Belloni, David Airlie, dri-devel, linux-kernel,
	Boris Brezillon, Peter Rosin, linux-arm-kernel

Hi Peter.

(Hijacking this thread as I lost the orginal mails)

> > 
> > I found an unfortunate issue while recoding plane handling to use
> > drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
> > which is not correct. I simply fixed it (patch 1/4), but maybe that
> > will cause regressions for unsuspecting users who simply assumed
> > that the clockwise rotation was correct? I don't know what to do
> > about that? Adding an option to get the old broken behavior seems
> > useless, wouldn't it be just as easy to just fix whatever app to
> > rotate the other way instead of adding an option somewhere?
> 
> Hm, rotation support has been added before the standard rotation
> property was created, and at that time I assumed rotation was clockwise
> (which apparently was an unwise choice). Anyway, I don't have a
> solution for this problem, so I'll let Nicolas decide if it's
> acceptable to change the rotation behavior.
> 
> > 
> > I have only tested this series on sama5d3, but I did check the docs
> > for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
> > and sam9x35) supported by the driver (relevant to patch 4/4).

I wonder if, when this code path is anyway touched, could benefit
from drm_rect_rotate().

It is obviously not a simple replacement, but could it be used then
I hope the resulting code is simpler.

	Sam

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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
  2019-01-10 17:45 ` [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Boris Brezillon
  2019-01-10 20:16   ` Sam Ravnborg
@ 2019-01-10 21:24   ` Peter Rosin
  2019-01-11 14:18   ` Nicolas.Ferre
  2 siblings, 0 replies; 21+ messages in thread
From: Peter Rosin @ 2019-01-10 21:24 UTC (permalink / raw)
  To: Boris Brezillon
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On 2019-01-10 18:45, Boris Brezillon wrote:
> On Thu, 10 Jan 2019 15:10:28 +0000
> Peter Rosin <peda@axentia.se> wrote:
> 
>> Hi!
>>
>> I found an unfortunate issue while recoding plane handling to use
>> drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
>> which is not correct. I simply fixed it (patch 1/4), but maybe that
>> will cause regressions for unsuspecting users who simply assumed
>> that the clockwise rotation was correct? I don't know what to do
>> about that? Adding an option to get the old broken behavior seems
>> useless, wouldn't it be just as easy to just fix whatever app to
>> rotate the other way instead of adding an option somewhere?
> 
> Hm, rotation support has been added before the standard rotation
> property was created, and at that time I assumed rotation was clockwise
> (which apparently was an unwise choice). Anyway, I don't have a
> solution for this problem, so I'll let Nicolas decide if it's
> acceptable to change the rotation behavior.

Speaking of unwise, fbcon rotation is clockwise and drm rotation
is counterclockwise. 'nuff said.

Cheers,
Peter
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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
  2019-01-10 20:16   ` Sam Ravnborg
@ 2019-01-11  9:16     ` Peter Rosin
  0 siblings, 0 replies; 21+ messages in thread
From: Peter Rosin @ 2019-01-11  9:16 UTC (permalink / raw)
  To: Sam Ravnborg, Boris Brezillon
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On 2019-01-10 21:16, Sam Ravnborg wrote:
> Hi Peter.
> 
> (Hijacking this thread as I lost the orginal mails)

Assuming you wanted to reply to this patch?
https://patchwork.kernel.org/patch/10753571/

>>> I found an unfortunate issue while recoding plane handling to use
>>> drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
>>> which is not correct. I simply fixed it (patch 1/4), but maybe that
>>> will cause regressions for unsuspecting users who simply assumed
>>> that the clockwise rotation was correct? I don't know what to do
>>> about that? Adding an option to get the old broken behavior seems
>>> useless, wouldn't it be just as easy to just fix whatever app to
>>> rotate the other way instead of adding an option somewhere?
>>
>> Hm, rotation support has been added before the standard rotation
>> property was created, and at that time I assumed rotation was clockwise
>> (which apparently was an unwise choice). Anyway, I don't have a
>> solution for this problem, so I'll let Nicolas decide if it's
>> acceptable to change the rotation behavior.
>>
>>> I have only tested this series on sama5d3, but I did check the docs
>>> for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
>>> and sam9x35) supported by the driver (relevant to patch 4/4).
> 
> I wonder if, when this code path is anyway touched, could benefit
> from drm_rect_rotate().
> 
> It is obviously not a simple replacement, but could it be used then
> I hope the resulting code is simpler.

What are you referring to that goes beyond what is done in patch 3/4
in this series? After setting up the strides, the only use of src_[xywh]
are to calculate the scaling factors, and for that the position is
irrelevant. I.e. src_x and src_y are not used. Sure, in some theoretical
sense it might be good if src_[xy] are also transformed into the rotated
coordinate system along with src_[wh], but it seems a bit backwards to
switch over to struct drm_rect when the interesting properties are the
width and height, not the coordinates of the corners. No strong feelings
on the issue though...

Cheers,
Peter
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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
  2019-01-10 17:48   ` Boris Brezillon
@ 2019-01-11 13:29     ` Peter Rosin
  2019-01-11 14:14       ` Nicolas.Ferre
  0 siblings, 1 reply; 21+ messages in thread
From: Peter Rosin @ 2019-01-11 13:29 UTC (permalink / raw)
  To: Boris Brezillon
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On 2019-01-10 18:48, Boris Brezillon wrote:
> On Thu, 10 Jan 2019 15:10:39 +0000
> Peter Rosin <peda@axentia.se> wrote:
> 
>> The destination crtc rectangle is independent of source plane rotation.
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
>> ---
>>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 3 ---
>>  1 file changed, 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>> index ea8fc0deb814..d6f93f029020 100644
>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>> @@ -642,9 +642,6 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
>>  	 * Swap width and size in case of 90 or 270 degrees rotation
>>  	 */
>>  	if (drm_rotation_90_or_270(state->base.rotation)) {
>> -		tmp = state->crtc_w;
>> -		state->crtc_w = state->crtc_h;
>> -		state->crtc_h = tmp;
> 
> Again, I guess I assumed ->crtc_h/w were the width and height before
> rotation when I initially added rotation support.

And I thought so too, possibly since I have only been doing drm-stuff
with this driver, but I also suspect that the incompleteness of the
libdrm modetest program is to blame. I don't think it's possible to
specify individual src and dst rectangles with it, and that seems
rather limiting when dealing with rotated planes. I can easily see
why someone using modetest thinks the crtc rect should be rotated by
the driver...

> This change might break users too.

Right you are, and the same impossible scenario. Fix things to do the
right thing and risk breaking users, or don't and preserve the buggy
non-portable issues of the driver making it unusable for others.

I don't care either way, because rotating planes with this stride-
method is practically useless here. It simply requires to much
memory bandwidth. I might work ok for smaller panels with lower
pixel clock frequencies though? I think the LCDC might read the same
data more than once when data is not in the "natural" order? (no,
I do not need an answer to this question, and I do not have time to
dig in this area at the moment...)

However, if you can't do both patch 1 and 2 (because users regress),
then patch 3 is no good either. The reason is that
drm_atomic_helper_check_plane_state assumes the rotational
properties fixed by patch 1 and 2, and the behavior is "odd" if you
have that wrong.

Cheers,
Peter

>>  		tmp = state->src_w;
>>  		state->src_w = state->src_h;
>>  		state->src_h = tmp;
> 

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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
  2019-01-11 13:29     ` Peter Rosin
@ 2019-01-11 14:14       ` Nicolas.Ferre
  0 siblings, 0 replies; 21+ messages in thread
From: Nicolas.Ferre @ 2019-01-11 14:14 UTC (permalink / raw)
  To: peda, bbrezillon
  Cc: alexandre.belloni, airlied, Joshua.Henderson, linux-kernel,
	dri-devel, boris.brezillon, linux-arm-kernel

On 11/01/2019 at 14:29, Peter Rosin wrote:
> On 2019-01-10 18:48, Boris Brezillon wrote:
>> On Thu, 10 Jan 2019 15:10:39 +0000
>> Peter Rosin <peda@axentia.se> wrote:
>>
>>> The destination crtc rectangle is independent of source plane rotation.
>>>
>>> Signed-off-by: Peter Rosin <peda@axentia.se>
>>> ---
>>>   drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 3 ---
>>>   1 file changed, 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>>> index ea8fc0deb814..d6f93f029020 100644
>>> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>>> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
>>> @@ -642,9 +642,6 @@ static int atmel_hlcdc_plane_atomic_check(struct drm_plane *p,
>>>   	 * Swap width and size in case of 90 or 270 degrees rotation
>>>   	 */
>>>   	if (drm_rotation_90_or_270(state->base.rotation)) {
>>> -		tmp = state->crtc_w;
>>> -		state->crtc_w = state->crtc_h;
>>> -		state->crtc_h = tmp;
>>
>> Again, I guess I assumed ->crtc_h/w were the width and height before
>> rotation when I initially added rotation support.
> 
> And I thought so too, possibly since I have only been doing drm-stuff
> with this driver, but I also suspect that the incompleteness of the
> libdrm modetest program is to blame. I don't think it's possible to
> specify individual src and dst rectangles with it, and that seems
> rather limiting when dealing with rotated planes. I can easily see
> why someone using modetest thinks the crtc rect should be rotated by
> the driver...
> 
>> This change might break users too.
> 
> Right you are, and the same impossible scenario. Fix things to do the
> right thing and risk breaking users, or don't and preserve the buggy
> non-portable issues of the driver making it unusable for others.

I understand that we are the only ones to be different here. My 
colleague Josh also helped me grasp the implications of this issue.

I would say that we mustn't be different. So please consider fixing 
this. Some users might have started something with rotations but we'll 
make sure to help them with the issue encountered and our additional DRM 
libraries (like libplanes) can be fixed easily to make this change 
transparent.

> I don't care either way, because rotating planes with this stride-
> method is practically useless here. It simply requires to much
> memory bandwidth. I might work ok for smaller panels with lower
> pixel clock frequencies though?

Rotation works for our use cases.

> I think the LCDC might read the same
> data more than once when data is not in the "natural" order? (no,
> I do not need an answer to this question, and I do not have time to
> dig in this area at the moment...)
> 
> However, if you can't do both patch 1 and 2 (because users regress),
> then patch 3 is no good either. The reason is that
> drm_atomic_helper_check_plane_state assumes the rotational
> properties fixed by patch 1 and 2, and the behavior is "odd" if you
> have that wrong.

Thanks for continuing the discussion Boris and thanks to Peter for this 
work. You have my opinion: please go-on with the fix.

Best regards,
   Nicolas

>>>   		tmp = state->src_w;
>>>   		state->src_w = state->src_h;
>>>   		state->src_h = tmp;
>>
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 


-- 
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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
  2019-01-10 17:45 ` [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Boris Brezillon
  2019-01-10 20:16   ` Sam Ravnborg
  2019-01-10 21:24   ` Peter Rosin
@ 2019-01-11 14:18   ` Nicolas.Ferre
  2 siblings, 0 replies; 21+ messages in thread
From: Nicolas.Ferre @ 2019-01-11 14:18 UTC (permalink / raw)
  To: bbrezillon, peda
  Cc: alexandre.belloni, airlied, Joshua.Henderson, linux-kernel,
	dri-devel, boris.brezillon, linux-arm-kernel

On 10/01/2019 at 18:45, Boris Brezillon wrote:
> On Thu, 10 Jan 2019 15:10:28 +0000
> Peter Rosin <peda@axentia.se> wrote:
> 
>> Hi!
>>
>> I found an unfortunate issue while recoding plane handling to use
>> drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
>> which is not correct. I simply fixed it (patch 1/4), but maybe that
>> will cause regressions for unsuspecting users who simply assumed
>> that the clockwise rotation was correct? I don't know what to do
>> about that? Adding an option to get the old broken behavior seems
>> useless, wouldn't it be just as easy to just fix whatever app to
>> rotate the other way instead of adding an option somewhere?
> 
> Hm, rotation support has been added before the standard rotation
> property was created, and at that time I assumed rotation was clockwise
> (which apparently was an unwise choice). Anyway, I don't have a
> solution for this problem, so I'll let Nicolas decide if it's
> acceptable to change the rotation behavior.

Yes, being consistent with standard DRM sub-system is far more important 
in my opinion.

Best regards,
   Nicolas

>> I have only tested this series on sama5d3, but I did check the docs
>> for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
>> and sam9x35) supported by the driver (relevant to patch 4/4).
> 
> Thanks for addressing those problems.
> 
>>
>> Cheers,
>> Peter
>>
>> Peter Rosin (4):
>>    drm/atmel-hlcdc: rotate planes counterclockwise
>>    drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
>>    drm/atmel-hlcdc: fix clipping of planes
>>    drm/atmel-hlcdc: do not immediately disable planes, wait for next
>>      frame
>>
>>   drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 179 +++++++++---------------
>>   1 file changed, 67 insertions(+), 112 deletions(-)
>>
> 
> 


-- 
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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame
  2019-01-10 19:25       ` Boris Brezillon
@ 2019-01-11 14:29         ` Peter Rosin
  2019-01-16 14:45           ` Boris Brezillon
  0 siblings, 1 reply; 21+ messages in thread
From: Peter Rosin @ 2019-01-11 14:29 UTC (permalink / raw)
  To: Boris Brezillon
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On 2019-01-10 20:25, Boris Brezillon wrote:
> On Thu, 10 Jan 2019 18:51:21 +0000
> Peter Rosin <peda@axentia.se> wrote:
> 
>> On 2019-01-10 18:29, Boris Brezillon wrote:
>>> On Thu, 10 Jan 2019 15:10:48 +0000
>>> Peter Rosin <peda@axentia.se> wrote:
>>>   
>>>> The A2Q and UPDATE bits have no effect in the channel disable registers.
>>>> However, since they are present, assume that the intention is to disable
>>>> planes, not immediately as indicated by the RST bit, but on the next
>>>> frame shift since that is what A2Q and UPDATE means in the channel enable
>>>> registers.
>>>>
>>>> Disabling the plane on the next frame shift is done with the EN bit,
>>>> so use that.  
>>>
>>> It's been a long time, but I think I had a good reason for forcing a
>>> reset. IIRC, when you don't do that and the CRTC is disabled before the
>>> plane, the EN bit stays around, and next time you queue a plane update,
>>> you'll start with an invalid buf pointer.  
>>
>> It might be possible to clear the EN bit in ...CHDR before enabling the
>> plane in ...CHER. Or is that too late?
> 
> I think I tried that, but I'm not sure (BTW, this change was done in
> bd4248bb5e8b ("drm: atmel-hlcdc: reset layer A2Q and UPDATE bits when

That patch is a big fat NOP if you read the documentation. Those bits
are marked with a '-' for all LCDC channel disable registers, for all
supported chips IIUC. Are the effects of those bits mentioned in any
errata?

It would be good with a comment that the present undocumented disable
method is intentional. That would have kept me from assuming the whole
thing was just copy-paste junk from ..._enable that happened to work.

>> disabling it")). Anyway, I'm not even sure this is still needed now
>> that atomic updates have a wait_for_flip_done/vblank() in the commit
>> path.

The documentation for the RST bit states "Resets the layer immediately.
The frame is aborted." which sounds a bit scary and heavy-handed. But
again, I don't know what that actually means and what the effects are
but that was the reason for me wanting to avoid the RST bit.

Cheers,
Peter

>> But this patch is not overly
>> important, I just wanted to avoid the resulting "black hole" when the
>> plane DMA is disabled mid-frame. But disabling planes is probably not
>> something that happens frequently and will perhaps not be noticed at
>> all...
> 
> Okay. Other patches look good to me, I'm just waiting for Nicolas
> feedback before applying them.
> 

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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame
  2019-01-11 14:29         ` Peter Rosin
@ 2019-01-16 14:45           ` Boris Brezillon
  0 siblings, 0 replies; 21+ messages in thread
From: Boris Brezillon @ 2019-01-16 14:45 UTC (permalink / raw)
  To: Peter Rosin
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On Fri, 11 Jan 2019 14:29:28 +0000
Peter Rosin <peda@axentia.se> wrote:

> On 2019-01-10 20:25, Boris Brezillon wrote:
> > On Thu, 10 Jan 2019 18:51:21 +0000
> > Peter Rosin <peda@axentia.se> wrote:
> >   
> >> On 2019-01-10 18:29, Boris Brezillon wrote:  
> >>> On Thu, 10 Jan 2019 15:10:48 +0000
> >>> Peter Rosin <peda@axentia.se> wrote:
> >>>     
> >>>> The A2Q and UPDATE bits have no effect in the channel disable registers.
> >>>> However, since they are present, assume that the intention is to disable
> >>>> planes, not immediately as indicated by the RST bit, but on the next
> >>>> frame shift since that is what A2Q and UPDATE means in the channel enable
> >>>> registers.
> >>>>
> >>>> Disabling the plane on the next frame shift is done with the EN bit,
> >>>> so use that.    
> >>>
> >>> It's been a long time, but I think I had a good reason for forcing a
> >>> reset. IIRC, when you don't do that and the CRTC is disabled before the
> >>> plane, the EN bit stays around, and next time you queue a plane update,
> >>> you'll start with an invalid buf pointer.    
> >>
> >> It might be possible to clear the EN bit in ...CHDR before enabling the
> >> plane in ...CHER. Or is that too late?  
> > 
> > I think I tried that, but I'm not sure (BTW, this change was done in
> > bd4248bb5e8b ("drm: atmel-hlcdc: reset layer A2Q and UPDATE bits when  
> 
> That patch is a big fat NOP if you read the documentation. Those bits
> are marked with a '-' for all LCDC channel disable registers, for all
> supported chips IIUC. Are the effects of those bits mentioned in any
> errata?

IIRC, it was not documented in the datasheet, but this came out during
a discussion with the IP designer.

> 
> It would be good with a comment that the present undocumented disable
> method is intentional.

Yes, I should have added a comment about that, my bad.

> That would have kept me from assuming the whole
> thing was just copy-paste junk from ..._enable that happened to work.
> 
> >> disabling it")). Anyway, I'm not even sure this is still needed now
> >> that atomic updates have a wait_for_flip_done/vblank() in the commit
> >> path.  
> 
> The documentation for the RST bit states "Resets the layer immediately.
> The frame is aborted." which sounds a bit scary and heavy-handed. But
> again, I don't know what that actually means and what the effects are
> but that was the reason for me wanting to avoid the RST bit.

As I said, I'm not even sure the problem I was trying to fix still
exists.

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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
  2019-01-10 15:10 [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Peter Rosin
                   ` (4 preceding siblings ...)
  2019-01-10 17:45 ` [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Boris Brezillon
@ 2019-01-27  8:27 ` Boris Brezillon
  2019-01-31 13:13   ` Peter Rosin
  5 siblings, 1 reply; 21+ messages in thread
From: Boris Brezillon @ 2019-01-27  8:27 UTC (permalink / raw)
  To: Peter Rosin
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On Thu, 10 Jan 2019 15:10:28 +0000
Peter Rosin <peda@axentia.se> wrote:

> Hi!
> 
> I found an unfortunate issue while recoding plane handling to use
> drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
> which is not correct. I simply fixed it (patch 1/4), but maybe that
> will cause regressions for unsuspecting users who simply assumed
> that the clockwise rotation was correct? I don't know what to do
> about that? Adding an option to get the old broken behavior seems
> useless, wouldn't it be just as easy to just fix whatever app to
> rotate the other way instead of adding an option somewhere?
> 
> I have only tested this series on sama5d3, but I did check the docs
> for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
> and sam9x35) supported by the driver (relevant to patch 4/4).
> 
> Cheers,
> Peter
> 
> Peter Rosin (4):
>   drm/atmel-hlcdc: rotate planes counterclockwise
>   drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
>   drm/atmel-hlcdc: fix clipping of planes

Queued patches 1-3 to drm-misc-next.

>   drm/atmel-hlcdc: do not immediately disable planes, wait for next
>     frame

Still waiting for Nicolas feedback on this one.


Thanks,

Boris

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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
  2019-01-27  8:27 ` Boris Brezillon
@ 2019-01-31 13:13   ` Peter Rosin
  2019-01-31 13:21     ` Boris Brezillon
  0 siblings, 1 reply; 21+ messages in thread
From: Peter Rosin @ 2019-01-31 13:13 UTC (permalink / raw)
  To: Boris Brezillon
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On 2019-01-27 09:27, Boris Brezillon wrote:
> On Thu, 10 Jan 2019 15:10:28 +0000
> Peter Rosin <peda@axentia.se> wrote:
> 
>> Hi!
>>
>> I found an unfortunate issue while recoding plane handling to use
>> drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
>> which is not correct. I simply fixed it (patch 1/4), but maybe that
>> will cause regressions for unsuspecting users who simply assumed
>> that the clockwise rotation was correct? I don't know what to do
>> about that? Adding an option to get the old broken behavior seems
>> useless, wouldn't it be just as easy to just fix whatever app to
>> rotate the other way instead of adding an option somewhere?
>>
>> I have only tested this series on sama5d3, but I did check the docs
>> for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
>> and sam9x35) supported by the driver (relevant to patch 4/4).
>>
>> Cheers,
>> Peter
>>
>> Peter Rosin (4):
>>   drm/atmel-hlcdc: rotate planes counterclockwise
>>   drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
>>   drm/atmel-hlcdc: fix clipping of planes
> 
> Queued patches 1-3 to drm-misc-next.

Great, thanks.

>>   drm/atmel-hlcdc: do not immediately disable planes, wait for next
>>     frame
> 
> Still waiting for Nicolas feedback on this one.

[Adding back Nicolas, he seems to have gone missing from the list
recipients.]

I have done some testing of that patch and for me it's a definite
improvement. The test I did was removing a white plane from a white
background. Without the patch, the driver will output black where
the plane was for the current frame (since the driver does that
disc-area thing for the largest hidden part of the background).
With the patch, I get no visual glitches when removing a plane.

I use a plane to scroll a text, and if you know what to look for,
the black rectangle that flickers by as the plane with the scrolling
text is removed is little bit disturbing. Not a significant problem,
and maybe only geeks notice it, but still...

Just wanted to say that the resulting "black hole" mentioned in the
other thread really does exist and that the patch may make sense
beyond the fact that it removes usage of undocumented features.

I have not seen any bad side effects fro the patch, but admittedly
my testing was very limited and I did not try to remove the plane
while doing other stuff with the driver. So, there might still be
reasons for removing planes immediately...

Cheers,
Peter
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^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues
  2019-01-31 13:13   ` Peter Rosin
@ 2019-01-31 13:21     ` Boris Brezillon
  0 siblings, 0 replies; 21+ messages in thread
From: Boris Brezillon @ 2019-01-31 13:21 UTC (permalink / raw)
  To: Peter Rosin
  Cc: Alexandre Belloni, David Airlie, linux-kernel, dri-devel,
	Boris Brezillon, linux-arm-kernel

On Thu, 31 Jan 2019 13:13:22 +0000
Peter Rosin <peda@axentia.se> wrote:

> On 2019-01-27 09:27, Boris Brezillon wrote:
> > On Thu, 10 Jan 2019 15:10:28 +0000
> > Peter Rosin <peda@axentia.se> wrote:
> >   
> >> Hi!
> >>
> >> I found an unfortunate issue while recoding plane handling to use
> >> drm_atomic_helper_check_plane_state(). The driver rotates clockwise,
> >> which is not correct. I simply fixed it (patch 1/4), but maybe that
> >> will cause regressions for unsuspecting users who simply assumed
> >> that the clockwise rotation was correct? I don't know what to do
> >> about that? Adding an option to get the old broken behavior seems
> >> useless, wouldn't it be just as easy to just fix whatever app to
> >> rotate the other way instead of adding an option somewhere?
> >>
> >> I have only tested this series on sama5d3, but I did check the docs
> >> for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35
> >> and sam9x35) supported by the driver (relevant to patch 4/4).
> >>
> >> Cheers,
> >> Peter
> >>
> >> Peter Rosin (4):
> >>   drm/atmel-hlcdc: rotate planes counterclockwise
> >>   drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated
> >>   drm/atmel-hlcdc: fix clipping of planes  
> > 
> > Queued patches 1-3 to drm-misc-next.  
> 
> Great, thanks.
> 
> >>   drm/atmel-hlcdc: do not immediately disable planes, wait for next
> >>     frame  
> > 
> > Still waiting for Nicolas feedback on this one.  
> 
> [Adding back Nicolas, he seems to have gone missing from the list
> recipients.]
> 
> I have done some testing of that patch and for me it's a definite
> improvement. The test I did was removing a white plane from a white
> background. Without the patch, the driver will output black where
> the plane was for the current frame (since the driver does that
> disc-area thing for the largest hidden part of the background).
> With the patch, I get no visual glitches when removing a plane.
> 
> I use a plane to scroll a text, and if you know what to look for,
> the black rectangle that flickers by as the plane with the scrolling
> text is removed is little bit disturbing. Not a significant problem,
> and maybe only geeks notice it, but still...
> 
> Just wanted to say that the resulting "black hole" mentioned in the
> other thread really does exist and that the patch may make sense
> beyond the fact that it removes usage of undocumented features.
> 
> I have not seen any bad side effects fro the patch, but admittedly
> my testing was very limited and I did not try to remove the plane
> while doing other stuff with the driver. So, there might still be
> reasons for removing planes immediately...

Since everything is now synchronized on vsync events thanks to the
atomic modeset infra (including plane/crtc disable requests), I think
the problem I was trying to fix at the time no longer exists (might
re-appear if we start supporting async plane disable requests which is
anyway not supported by the core). So I think I'll just apply your
patch.

Thanks,

Boris

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^ permalink raw reply	[flat|nested] 21+ messages in thread

end of thread, back to index

Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-01-10 15:10 [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Peter Rosin
2019-01-10 15:10 ` [PATCH 1/4] drm/atmel-hlcdc: rotate planes counterclockwise Peter Rosin
2019-01-10 15:10 ` [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated Peter Rosin
2019-01-10 17:48   ` Boris Brezillon
2019-01-11 13:29     ` Peter Rosin
2019-01-11 14:14       ` Nicolas.Ferre
2019-01-10 15:10 ` [PATCH 3/4] drm/atmel-hlcdc: fix clipping of planes Peter Rosin
2019-01-10 15:10 ` [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame Peter Rosin
2019-01-10 17:29   ` Boris Brezillon
2019-01-10 18:51     ` Peter Rosin
2019-01-10 19:25       ` Boris Brezillon
2019-01-11 14:29         ` Peter Rosin
2019-01-16 14:45           ` Boris Brezillon
2019-01-10 17:45 ` [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Boris Brezillon
2019-01-10 20:16   ` Sam Ravnborg
2019-01-11  9:16     ` Peter Rosin
2019-01-10 21:24   ` Peter Rosin
2019-01-11 14:18   ` Nicolas.Ferre
2019-01-27  8:27 ` Boris Brezillon
2019-01-31 13:13   ` Peter Rosin
2019-01-31 13:21     ` Boris Brezillon

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