diff mbox series

[v3] drm/tidss: dispc: Rewrite naive plane positioning code

Message ID 20200213104419.29617-1-jsarha@ti.com
State Superseded
Headers show
Series [v3] drm/tidss: dispc: Rewrite naive plane positioning code | expand

Commit Message

Jyri Sarha Feb. 13, 2020, 10:44 a.m. UTC
The old implementation of placing planes on the CRTC while configuring
the planes was naive and relied on the order in which the planes were
configured, enabled, and disabled. The situation where a plane's zpos
was changed on the fly was completely broken. The usual symptoms of
this problem was scrambled display and a flood of sync lost errors,
when a plane was active in two layers at the same time, or a missing
plane, in case when a layer was accidentally disabled.

The rewrite takes a more straight forward approach when HW is
concerned. The plane positioning registers are in the CRTC (or
actually OVR) register space and it is more natural to configure them
in a one go when configuring the CRTC. To do this we need make sure we
have all the planes on the updated CRTCs in the new atomic state. The
untouched planes on changed CRTCs are added to the atomic state in
tidss_atomic_check().

Signed-off-by: Jyri Sarha <jsarha@ti.com>

---
 drivers/gpu/drm/tidss/tidss_crtc.c  | 52 +++++++++++++++++++++++++++
 drivers/gpu/drm/tidss/tidss_dispc.c | 55 +++++++++++------------------
 drivers/gpu/drm/tidss/tidss_dispc.h |  5 +++
 drivers/gpu/drm/tidss/tidss_kms.c   | 33 ++++++++++++++++-
 4 files changed, 109 insertions(+), 36 deletions(-)

-- 
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Comments

Tomi Valkeinen Feb. 13, 2020, 10:49 a.m. UTC | #1
On 13/02/2020 12:44, Jyri Sarha wrote:

> +	/*

> +	 * If a plane on a CRTC changes add all active planes on that

> +	 * CRTC to the atomic state. This is needed for updating the

> +	 * plane positions in tidss_crtc_position_planes() which is

> +	 * called from crtc_atomic_enable() and crtc_atomic_flush().

> +	 * The update is needed for x,y-position changes too, so

> +	 * zpos_changed condition is not enough and we need this if

> +	 * planes_changed is true too.

> +	 */

> +	for_each_new_crtc_in_state(state, crtc, cstate, i) {

> +		if (cstate->zpos_changed || cstate->planes_changed) {

> +			ret = drm_atomic_add_affected_planes(state, crtc);

> +			if (ret)

> +				return ret;

> +		}

> +	}


I think 99.99...% of the commits are such where only planes' fb address is changed. I think 
"planes_changed" is true for these. I wonder if it would be a sensible optimization to skip this for 
those 99.99...% cases. Can we detect that easily?

Well, we haven't optimized for those 99.99...% cases anywhere else either, so it's possible it 
doesn't matter.

  Tomi

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Jyri Sarha Feb. 13, 2020, 11:52 a.m. UTC | #2
On 13/02/2020 12:49, Tomi Valkeinen wrote:
> On 13/02/2020 12:44, Jyri Sarha wrote:
> 
>> +    /*
>> +     * If a plane on a CRTC changes add all active planes on that
>> +     * CRTC to the atomic state. This is needed for updating the
>> +     * plane positions in tidss_crtc_position_planes() which is
>> +     * called from crtc_atomic_enable() and crtc_atomic_flush().
>> +     * The update is needed for x,y-position changes too, so
>> +     * zpos_changed condition is not enough and we need this if
>> +     * planes_changed is true too.
>> +     */
>> +    for_each_new_crtc_in_state(state, crtc, cstate, i) {
>> +        if (cstate->zpos_changed || cstate->planes_changed) {
>> +            ret = drm_atomic_add_affected_planes(state, crtc);
>> +            if (ret)
>> +                return ret;
>> +        }
>> +    }
> 
> I think 99.99...% of the commits are such where only planes' fb address
> is changed. I think "planes_changed" is true for these. I wonder if it
> would be a sensible optimization to skip this for those 99.99...% cases.
> Can we detect that easily?
> 

Sure by looping all planes in the state through with
for_each_oldnew_plane_in_state() and checking if crtc_x or crtc_y has
changed. But then again writing the positions of max 4 planes is really
not that heavy operation. There is more calculation to do and more
registers to write when updating the fp, so I do not think avoiding the
OVR update justifies the extra complexity.

> Well, we haven't optimized for those 99.99...% cases anywhere else
> either, so it's possible it doesn't matter.
>
Jyri Sarha Feb. 13, 2020, 7:29 p.m. UTC | #3
On 13/02/2020 13:52, Jyri Sarha wrote:
> On 13/02/2020 12:49, Tomi Valkeinen wrote:
>> On 13/02/2020 12:44, Jyri Sarha wrote:
>>
>>> +    /*
>>> +     * If a plane on a CRTC changes add all active planes on that
>>> +     * CRTC to the atomic state. This is needed for updating the
>>> +     * plane positions in tidss_crtc_position_planes() which is
>>> +     * called from crtc_atomic_enable() and crtc_atomic_flush().
>>> +     * The update is needed for x,y-position changes too, so
>>> +     * zpos_changed condition is not enough and we need this if
>>> +     * planes_changed is true too.
>>> +     */
>>> +    for_each_new_crtc_in_state(state, crtc, cstate, i) {
>>> +        if (cstate->zpos_changed || cstate->planes_changed) {
>>> +            ret = drm_atomic_add_affected_planes(state, crtc);
>>> +            if (ret)
>>> +                return ret;
>>> +        }
>>> +    }
>>
>> I think 99.99...% of the commits are such where only planes' fb address
>> is changed. I think "planes_changed" is true for these. I wonder if it
>> would be a sensible optimization to skip this for those 99.99...% cases.
>> Can we detect that easily?
>>
> 
> Sure by looping all planes in the state through with
> for_each_oldnew_plane_in_state() and checking if crtc_x or crtc_y has
> changed. But then again writing the positions of max 4 planes is really
> not that heavy operation. There is more calculation to do and more
> registers to write when updating the fp, so I do not think avoiding the
> OVR update justifies the extra complexity.
> 

Well, I implemented this anyway just for the fun of it. After all the
added complexity is not that much, since we already have an extended
CRTC state. Judge your self, I'll send v4 shortly.

Best regards,
Jyri

>> Well, we haven't optimized for those 99.99...% cases anywhere else
>> either, so it's possible it doesn't matter.
>>
> 
> 
> 
> 
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/tidss/tidss_crtc.c b/drivers/gpu/drm/tidss/tidss_crtc.c
index 032c31ee2820..36478c54784b 100644
--- a/drivers/gpu/drm/tidss/tidss_crtc.c
+++ b/drivers/gpu/drm/tidss/tidss_crtc.c
@@ -17,6 +17,7 @@ 
 #include "tidss_dispc.h"
 #include "tidss_drv.h"
 #include "tidss_irq.h"
+#include "tidss_plane.h"
 
 /* Page flip and frame done IRQs */
 
@@ -111,6 +112,53 @@  static int tidss_crtc_atomic_check(struct drm_crtc *crtc,
 	return dispc_vp_bus_check(dispc, hw_videoport, state);
 }
 
+/*
+ * This needs all affected planes to be present in the atomic
+ * state. The untouched planes are added to the state in
+ * tidss_atomic_check().
+ */
+static void tidss_crtc_position_planes(struct tidss_device *tidss,
+				       struct drm_crtc *crtc,
+				       struct drm_crtc_state *old_state,
+				       bool newmodeset)
+{
+	struct drm_atomic_state *ostate = old_state->state;
+	struct tidss_crtc *tcrtc = to_tidss_crtc(crtc);
+	struct drm_crtc_state *cstate = crtc->state;
+	int zpos;
+
+	if (!newmodeset && !cstate->zpos_changed && !cstate->planes_changed)
+		return;
+
+	for (zpos = 0; zpos < tidss->feat->num_planes; zpos++) {
+		struct drm_plane_state *pstate;
+		struct drm_plane *plane;
+		bool zpos_taken = false;
+		int i;
+
+		for_each_new_plane_in_state(ostate, plane, pstate, i) {
+			if (pstate->crtc != crtc || !pstate->visible)
+				continue;
+
+			if (pstate->normalized_zpos == zpos) {
+				zpos_taken = true;
+				break;
+			}
+		}
+
+		if (zpos_taken) {
+			struct tidss_plane *tplane = to_tidss_plane(plane);
+
+			dispc_ovr_set_plane(tidss->dispc, tplane->hw_plane_id,
+					    tcrtc->hw_videoport,
+					    pstate->crtc_x, pstate->crtc_y,
+					    zpos);
+		}
+		dispc_ovr_enable_layer(tidss->dispc, tcrtc->hw_videoport, zpos,
+				       zpos_taken);
+	}
+}
+
 static void tidss_crtc_atomic_flush(struct drm_crtc *crtc,
 				    struct drm_crtc_state *old_crtc_state)
 {
@@ -146,6 +194,9 @@  static void tidss_crtc_atomic_flush(struct drm_crtc *crtc,
 	/* Write vp properties to HW if needed. */
 	dispc_vp_setup(tidss->dispc, tcrtc->hw_videoport, crtc->state, false);
 
+	/* Update plane positions if needed. */
+	tidss_crtc_position_planes(tidss, crtc, old_crtc_state, false);
+
 	WARN_ON(drm_crtc_vblank_get(crtc) != 0);
 
 	spin_lock_irqsave(&ddev->event_lock, flags);
@@ -183,6 +234,7 @@  static void tidss_crtc_atomic_enable(struct drm_crtc *crtc,
 		return;
 
 	dispc_vp_setup(tidss->dispc, tcrtc->hw_videoport, crtc->state, true);
+	tidss_crtc_position_planes(tidss, crtc, old_state, true);
 
 	/* Turn vertical blanking interrupt reporting on. */
 	drm_crtc_vblank_on(crtc);
diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c
index eeb160dc047b..e79dad246b1e 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -281,11 +281,6 @@  struct dss_vp_data {
 	u32 *gamma_table;
 };
 
-struct dss_plane_data {
-	u32 zorder;
-	u32 hw_videoport;
-};
-
 struct dispc_device {
 	struct tidss_device *tidss;
 	struct device *dev;
@@ -307,8 +302,6 @@  struct dispc_device {
 
 	struct dss_vp_data vp_data[TIDSS_MAX_PORTS];
 
-	struct dss_plane_data plane_data[TIDSS_MAX_PLANES];
-
 	u32 *fourccs;
 	u32 num_fourccs;
 
@@ -1247,7 +1240,7 @@  int dispc_vp_set_clk_rate(struct dispc_device *dispc, u32 hw_videoport,
 /* OVR */
 static void dispc_k2g_ovr_set_plane(struct dispc_device *dispc,
 				    u32 hw_plane, u32 hw_videoport,
-				    u32 x, u32 y, u32 zpos)
+				    u32 x, u32 y, u32 layer)
 {
 	/* On k2g there is only one plane and no need for ovr */
 	dispc_vid_write(dispc, hw_plane, DISPC_VID_K2G_POSITION,
@@ -1256,44 +1249,43 @@  static void dispc_k2g_ovr_set_plane(struct dispc_device *dispc,
 
 static void dispc_am65x_ovr_set_plane(struct dispc_device *dispc,
 				      u32 hw_plane, u32 hw_videoport,
-				      u32 x, u32 y, u32 zpos)
+				      u32 x, u32 y, u32 layer)
 {
-	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(zpos),
+	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(layer),
 			hw_plane, 4, 1);
-	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(zpos),
+	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(layer),
 			x, 17, 6);
-	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(zpos),
+	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(layer),
 			y, 30, 19);
 }
 
 static void dispc_j721e_ovr_set_plane(struct dispc_device *dispc,
 				      u32 hw_plane, u32 hw_videoport,
-				      u32 x, u32 y, u32 zpos)
+				      u32 x, u32 y, u32 layer)
 {
-	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(zpos),
+	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(layer),
 			hw_plane, 4, 1);
-	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES2(zpos),
+	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES2(layer),
 			x, 13, 0);
-	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES2(zpos),
+	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES2(layer),
 			y, 29, 16);
 }
 
-static void dispc_ovr_set_plane(struct dispc_device *dispc,
-				u32 hw_plane, u32 hw_videoport,
-				u32 x, u32 y, u32 zpos)
+void dispc_ovr_set_plane(struct dispc_device *dispc, u32 hw_plane,
+			 u32 hw_videoport, u32 x, u32 y, u32 layer)
 {
 	switch (dispc->feat->subrev) {
 	case DISPC_K2G:
 		dispc_k2g_ovr_set_plane(dispc, hw_plane, hw_videoport,
-					x, y, zpos);
+					x, y, layer);
 		break;
 	case DISPC_AM65X:
 		dispc_am65x_ovr_set_plane(dispc, hw_plane, hw_videoport,
-					  x, y, zpos);
+					  x, y, layer);
 		break;
 	case DISPC_J721E:
 		dispc_j721e_ovr_set_plane(dispc, hw_plane, hw_videoport,
-					  x, y, zpos);
+					  x, y, layer);
 		break;
 	default:
 		WARN_ON(1);
@@ -1301,10 +1293,13 @@  static void dispc_ovr_set_plane(struct dispc_device *dispc,
 	}
 }
 
-static void dispc_ovr_enable_plane(struct dispc_device *dispc,
-				   u32 hw_videoport, u32 zpos, bool enable)
+void dispc_ovr_enable_layer(struct dispc_device *dispc,
+			    u32 hw_videoport, u32 layer, bool enable)
 {
-	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(zpos),
+	if (dispc->feat->subrev == DISPC_K2G)
+		return;
+
+	OVR_REG_FLD_MOD(dispc, hw_videoport, DISPC_OVR_ATTRIBUTES(layer),
 			!!enable, 0, 0);
 }
 
@@ -2070,21 +2065,11 @@  int dispc_plane_setup(struct dispc_device *dispc, u32 hw_plane,
 		VID_REG_FLD_MOD(dispc, hw_plane, DISPC_VID_ATTRIBUTES, 0,
 				28, 28);
 
-	dispc_ovr_set_plane(dispc, hw_plane, hw_videoport,
-			    state->crtc_x, state->crtc_y,
-			    state->normalized_zpos);
-
-	dispc->plane_data[hw_plane].zorder = state->normalized_zpos;
-	dispc->plane_data[hw_plane].hw_videoport = hw_videoport;
-
 	return 0;
 }
 
 int dispc_plane_enable(struct dispc_device *dispc, u32 hw_plane, bool enable)
 {
-	dispc_ovr_enable_plane(dispc, dispc->plane_data[hw_plane].hw_videoport,
-			       dispc->plane_data[hw_plane].zorder, enable);
-
 	VID_REG_FLD_MOD(dispc, hw_plane, DISPC_VID_ATTRIBUTES, !!enable, 0, 0);
 
 	return 0;
diff --git a/drivers/gpu/drm/tidss/tidss_dispc.h b/drivers/gpu/drm/tidss/tidss_dispc.h
index e65e6a2bb821..a4a68249e44b 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.h
+++ b/drivers/gpu/drm/tidss/tidss_dispc.h
@@ -94,6 +94,11 @@  extern const struct dispc_features dispc_j721e_feats;
 void dispc_set_irqenable(struct dispc_device *dispc, dispc_irq_t mask);
 dispc_irq_t dispc_read_and_clear_irqstatus(struct dispc_device *dispc);
 
+void dispc_ovr_set_plane(struct dispc_device *dispc, u32 hw_plane,
+			 u32 hw_videoport, u32 x, u32 y, u32 layer);
+void dispc_ovr_enable_layer(struct dispc_device *dispc,
+			    u32 hw_videoport, u32 layer, bool enable);
+
 void dispc_vp_prepare(struct dispc_device *dispc, u32 hw_videoport,
 		      const struct drm_crtc_state *state);
 void dispc_vp_enable(struct dispc_device *dispc, u32 hw_videoport,
diff --git a/drivers/gpu/drm/tidss/tidss_kms.c b/drivers/gpu/drm/tidss/tidss_kms.c
index 5311e0f1c551..ae461cabff4c 100644
--- a/drivers/gpu/drm/tidss/tidss_kms.c
+++ b/drivers/gpu/drm/tidss/tidss_kms.c
@@ -47,9 +47,40 @@  static const struct drm_mode_config_helper_funcs mode_config_helper_funcs = {
 	.atomic_commit_tail = tidss_atomic_commit_tail,
 };
 
+static int tidss_atomic_check(struct drm_device *ddev,
+			      struct drm_atomic_state *state)
+{
+	struct drm_crtc_state *cstate;
+	struct drm_crtc *crtc;
+	int ret, i;
+
+	ret = drm_atomic_helper_check(ddev, state);
+	if (ret)
+		return ret;
+
+	/*
+	 * If a plane on a CRTC changes add all active planes on that
+	 * CRTC to the atomic state. This is needed for updating the
+	 * plane positions in tidss_crtc_position_planes() which is
+	 * called from crtc_atomic_enable() and crtc_atomic_flush().
+	 * The update is needed for x,y-position changes too, so
+	 * zpos_changed condition is not enough and we need this if
+	 * planes_changed is true too.
+	 */
+	for_each_new_crtc_in_state(state, crtc, cstate, i) {
+		if (cstate->zpos_changed || cstate->planes_changed) {
+			ret = drm_atomic_add_affected_planes(state, crtc);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
 static const struct drm_mode_config_funcs mode_config_funcs = {
 	.fb_create = drm_gem_fb_create,
-	.atomic_check = drm_atomic_helper_check,
+	.atomic_check = tidss_atomic_check,
 	.atomic_commit = drm_atomic_helper_commit,
 };