[PATCHv3,3/8] drm/omap: add support for manually updated displays

Commit Message

Sebastian Reichel March 30, 2018, 5:18 p.m. UTC

This adds the required infrastructure for manually
updated displays, such as DSI command mode panels.

While those panels often support partial updates
we currently always do a full refresh. Display
will be refreshed when something calls the dirty
callback, such as libdrm's drmModeDirtyFB().

This is currently being implemented for the kernel
console and for Xorg. Weston currently does not
implement this and is known not to work on manually
updated displays.

Tested-by: Tony Lindgren <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>
---
 drivers/gpu/drm/omapdrm/omap_crtc.c | 107 +++++++++++++++++++++++++++++++++---
 drivers/gpu/drm/omapdrm/omap_crtc.h |   1 +
 drivers/gpu/drm/omapdrm/omap_fb.c   |  20 +++++++
 3 files changed, 120 insertions(+), 8 deletions(-)

Comments

Tomi Valkeinen April 20, 2018, 7:09 a.m. UTC | #1

Hi Sebastian,

On 30/03/18 20:18, Sebastian Reichel wrote:
> This adds the required infrastructure for manually
> updated displays, such as DSI command mode panels.
> 
> While those panels often support partial updates
> we currently always do a full refresh. Display
> will be refreshed when something calls the dirty
> callback, such as libdrm's drmModeDirtyFB().
> 
> This is currently being implemented for the kernel
> console and for Xorg. Weston currently does not
> implement this and is known not to work on manually
> updated displays.
> 
> Tested-by: Tony Lindgren <[e-mail]>
> Signed-off-by: Sebastian Reichel <[e-mail]>
> ---
>  drivers/gpu/drm/omapdrm/omap_crtc.c | 107 +++++++++++++++++++++++++++++++++---
>  drivers/gpu/drm/omapdrm/omap_crtc.h |   1 +
>  drivers/gpu/drm/omapdrm/omap_fb.c   |  20 +++++++
>  3 files changed, 120 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
> index b893985e4efb..1b91bff5bac6 100644
> --- a/drivers/gpu/drm/omapdrm/omap_crtc.c
> +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
> @@ -51,6 +51,7 @@ struct omap_crtc {
>  	bool pending;
>  	wait_queue_head_t pending_wait;
>  	struct drm_pending_vblank_event *event;
> +	struct delayed_work update_work;
>  
>  	void (*framedone_handler)(void *);
>  	void *framedone_handler_data;
> @@ -146,6 +147,25 @@ static void omap_crtc_dss_disconnect(struct omap_drm_private *priv,
>  static void omap_crtc_dss_start_update(struct omap_drm_private *priv,
>  				       enum omap_channel channel)
>  {
> +	priv->dispc_ops->mgr_enable(priv->dispc, channel, true);
> +}
> +
> +static bool omap_crtc_is_manually_updated(struct drm_crtc *crtc)
> +{
> +	struct drm_connector *connector;
> +	struct drm_connector_list_iter conn_iter;
> +	bool result = false;
> +
> +	drm_connector_list_iter_begin(crtc->dev, &conn_iter);
> +	drm_for_each_connector_iter(connector, &conn_iter) {
> +		if (connector->state->crtc != crtc)
> +			continue;
> +		result = omap_connector_get_manually_updated(connector);
> +		break;
> +	}
> +	drm_connector_list_iter_end(&conn_iter);

It would be much nicer if the is-manual flag was somehow conveyed from
connector/encoder to the crtc when doing modesetting. I don't know how
or where, so just thinking out loud. However, if we need to do such loop
as above, I think we should just do it once, perhaps in
omap_crtc_atomic_enable, and store the value in omap_crtc's private data.

> +
> +	return result;
>  }
>  
>  /* Called only from the encoder enable/disable and suspend/resume handlers. */
> @@ -157,12 +177,17 @@ static void omap_crtc_set_enabled(struct drm_crtc *crtc, bool enable)
>  	enum omap_channel channel = omap_crtc->channel;
>  	struct omap_irq_wait *wait;
>  	u32 framedone_irq, vsync_irq;
> +	bool is_manual = omap_crtc_is_manually_updated(crtc);
> +	enum omap_display_type type = omap_crtc_output[channel]->output_type;
>  	int ret;
>  
>  	if (WARN_ON(omap_crtc->enabled == enable))
>  		return;
>  
> -	if (omap_crtc_output[channel]->output_type == OMAP_DISPLAY_TYPE_HDMI) {
> +	if (is_manual)
> +		omap_irq_enable_framedone(crtc, enable);
> +
> +	if (is_manual || type == OMAP_DISPLAY_TYPE_HDMI) {
>  		priv->dispc_ops->mgr_enable(priv->dispc, channel, enable);
>  		omap_crtc->enabled = enable;
>  		return;

This doesn't look correct, omap_crtc_dss_start_update() already sets the
enable bit for manual update displays. And you don't want to set the
enable to false with manual update displays.

HDMI handling here is already a special case due to HW issues, so I'd
rather see the manual update handled separately from the HDMI.

> @@ -214,7 +239,6 @@ static void omap_crtc_set_enabled(struct drm_crtc *crtc, bool enable)
>  	}
>  }
>  
> -
>  static int omap_crtc_dss_enable(struct omap_drm_private *priv,
>  				enum omap_channel channel)
>  {
> @@ -378,6 +402,53 @@ void omap_crtc_framedone_irq(struct drm_crtc *crtc, uint32_t irqstatus)
>  	wake_up(&omap_crtc->pending_wait);
>  }
>  
> +void omap_crtc_flush(struct drm_crtc *crtc)
> +{
> +	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
> +
> +	if (!omap_crtc_is_manually_updated(crtc))
> +		return;
> +
> +	if (!delayed_work_pending(&omap_crtc->update_work))
> +		schedule_delayed_work(&omap_crtc->update_work, 0);
> +}

Why delayed work here?

It's actually not quite clear to me how manual update displays work with
DRM...

As far as I see, we have essentially two cases: 1) single buffering,
where the userspace must set an area in the fb dirty, which then
triggers the update, 2) multi buffering, which doesn't need fb dirty,
but just a page flip which triggers the update.

In the 2) case (which I think is the optimal case which all the modern
apps should use), there's no need for delayed work or any work, and the
code flow should be very similar to the auto-update model.

Also, as Daniel mentioned in "drm/omapdrm: Nuke
omap_framebuffer_get_next_connector()" thread, the dirtying mechanism in
the series is not valid.

 Tomi

Daniel Vetter April 20, 2018, 8:11 a.m. UTC | #2

On Fri, Apr 20, 2018 at 10:09:38AM +0300, Tomi Valkeinen wrote:
> Hi Sebastian,
> 
> On 30/03/18 20:18, Sebastian Reichel wrote:
> > This adds the required infrastructure for manually
> > updated displays, such as DSI command mode panels.
> > 
> > While those panels often support partial updates
> > we currently always do a full refresh. Display
> > will be refreshed when something calls the dirty
> > callback, such as libdrm's drmModeDirtyFB().
> > 
> > This is currently being implemented for the kernel
> > console and for Xorg. Weston currently does not
> > implement this and is known not to work on manually
> > updated displays.
> > 
> > Tested-by: Tony Lindgren <[e-mail]>
> > Signed-off-by: Sebastian Reichel <[e-mail]>
> > ---
> >  drivers/gpu/drm/omapdrm/omap_crtc.c | 107 +++++++++++++++++++++++++++++++++---
> >  drivers/gpu/drm/omapdrm/omap_crtc.h |   1 +
> >  drivers/gpu/drm/omapdrm/omap_fb.c   |  20 +++++++
> >  3 files changed, 120 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
> > index b893985e4efb..1b91bff5bac6 100644
> > --- a/drivers/gpu/drm/omapdrm/omap_crtc.c
> > +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
> > @@ -51,6 +51,7 @@ struct omap_crtc {
> >  	bool pending;
> >  	wait_queue_head_t pending_wait;
> >  	struct drm_pending_vblank_event *event;
> > +	struct delayed_work update_work;
> >  
> >  	void (*framedone_handler)(void *);
> >  	void *framedone_handler_data;
> > @@ -146,6 +147,25 @@ static void omap_crtc_dss_disconnect(struct omap_drm_private *priv,
> >  static void omap_crtc_dss_start_update(struct omap_drm_private *priv,
> >  				       enum omap_channel channel)
> >  {
> > +	priv->dispc_ops->mgr_enable(priv->dispc, channel, true);
> > +}
> > +
> > +static bool omap_crtc_is_manually_updated(struct drm_crtc *crtc)
> > +{
> > +	struct drm_connector *connector;
> > +	struct drm_connector_list_iter conn_iter;
> > +	bool result = false;
> > +
> > +	drm_connector_list_iter_begin(crtc->dev, &conn_iter);
> > +	drm_for_each_connector_iter(connector, &conn_iter) {
> > +		if (connector->state->crtc != crtc)
> > +			continue;
> > +		result = omap_connector_get_manually_updated(connector);
> > +		break;
> > +	}
> > +	drm_connector_list_iter_end(&conn_iter);
> 
> It would be much nicer if the is-manual flag was somehow conveyed from
> connector/encoder to the crtc when doing modesetting. I don't know how
> or where, so just thinking out loud. However, if we need to do such loop
> as above, I think we should just do it once, perhaps in
> omap_crtc_atomic_enable, and store the value in omap_crtc's private data.

Do it in your atomic_check code, and store it as a omap private bit in
omap_crtc_state. That guarantees you that it's always up-to-date, and will
never change (except when you get a completely new state).

Recomputing derived state like this as part of your atomic_commit code
isn't recommended much.
-Daniel

> 
> > +
> > +	return result;
> >  }
> >  
> >  /* Called only from the encoder enable/disable and suspend/resume handlers. */
> > @@ -157,12 +177,17 @@ static void omap_crtc_set_enabled(struct drm_crtc *crtc, bool enable)
> >  	enum omap_channel channel = omap_crtc->channel;
> >  	struct omap_irq_wait *wait;
> >  	u32 framedone_irq, vsync_irq;
> > +	bool is_manual = omap_crtc_is_manually_updated(crtc);
> > +	enum omap_display_type type = omap_crtc_output[channel]->output_type;
> >  	int ret;
> >  
> >  	if (WARN_ON(omap_crtc->enabled == enable))
> >  		return;
> >  
> > -	if (omap_crtc_output[channel]->output_type == OMAP_DISPLAY_TYPE_HDMI) {
> > +	if (is_manual)
> > +		omap_irq_enable_framedone(crtc, enable);
> > +
> > +	if (is_manual || type == OMAP_DISPLAY_TYPE_HDMI) {
> >  		priv->dispc_ops->mgr_enable(priv->dispc, channel, enable);
> >  		omap_crtc->enabled = enable;
> >  		return;
> 
> This doesn't look correct, omap_crtc_dss_start_update() already sets the
> enable bit for manual update displays. And you don't want to set the
> enable to false with manual update displays.
> 
> HDMI handling here is already a special case due to HW issues, so I'd
> rather see the manual update handled separately from the HDMI.
> 
> > @@ -214,7 +239,6 @@ static void omap_crtc_set_enabled(struct drm_crtc *crtc, bool enable)
> >  	}
> >  }
> >  
> > -
> >  static int omap_crtc_dss_enable(struct omap_drm_private *priv,
> >  				enum omap_channel channel)
> >  {
> > @@ -378,6 +402,53 @@ void omap_crtc_framedone_irq(struct drm_crtc *crtc, uint32_t irqstatus)
> >  	wake_up(&omap_crtc->pending_wait);
> >  }
> >  
> > +void omap_crtc_flush(struct drm_crtc *crtc)
> > +{
> > +	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
> > +
> > +	if (!omap_crtc_is_manually_updated(crtc))
> > +		return;
> > +
> > +	if (!delayed_work_pending(&omap_crtc->update_work))
> > +		schedule_delayed_work(&omap_crtc->update_work, 0);
> > +}
> 
> Why delayed work here?
> 
> It's actually not quite clear to me how manual update displays work with
> DRM...
> 
> As far as I see, we have essentially two cases: 1) single buffering,
> where the userspace must set an area in the fb dirty, which then
> triggers the update, 2) multi buffering, which doesn't need fb dirty,
> but just a page flip which triggers the update.
> 
> In the 2) case (which I think is the optimal case which all the modern
> apps should use), there's no need for delayed work or any work, and the
> code flow should be very similar to the auto-update model.
> 
> Also, as Daniel mentioned in "drm/omapdrm: Nuke
> omap_framebuffer_get_next_connector()" thread, the dirtying mechanism in
> the series is not valid.
> 
>  Tomi
> 
> -- 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> _______________________________________________
> dri-devel mailing list
> [e-mail]
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

Daniel Stone April 20, 2018, 10:19 a.m. UTC | #3

Hi Tomi,

On 20 April 2018 at 08:09, Tomi Valkeinen <[e-mail]> wrote:
> It's actually not quite clear to me how manual update displays work with
> DRM...
>
> As far as I see, we have essentially two cases: 1) single buffering,
> where the userspace must set an area in the fb dirty, which then
> triggers the update, 2) multi buffering, which doesn't need fb dirty,
> but just a page flip which triggers the update.
>
> In the 2) case (which I think is the optimal case which all the modern
> apps should use), there's no need for delayed work or any work, and the
> code flow should be very similar to the auto-update model.

Correct. There's been talk (and I think patches?) of adding a
per-plane dirty property, so userspace can as an optimisation inform
the kernel of the area changed between frames. But short of that, a
pageflip needs to trigger a full-plane update, with no dirtyfb
required.

Cheers,
Daniel
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Tony Lindgren April 20, 2018, 2:25 p.m. UTC | #4

Hi,

* Daniel Stone <[e-mail]> [180420 10:21]:
> Hi Tomi,
> 
> On 20 April 2018 at 08:09, Tomi Valkeinen <[e-mail]> wrote:
> > It's actually not quite clear to me how manual update displays work with
> > DRM...
> >
> > As far as I see, we have essentially two cases: 1) single buffering,
> > where the userspace must set an area in the fb dirty, which then
> > triggers the update, 2) multi buffering, which doesn't need fb dirty,
> > but just a page flip which triggers the update.
> >
> > In the 2) case (which I think is the optimal case which all the modern
> > apps should use), there's no need for delayed work or any work, and the
> > code flow should be very similar to the auto-update model.
> 
> Correct. There's been talk (and I think patches?) of adding a
> per-plane dirty property, so userspace can as an optimisation inform
> the kernel of the area changed between frames. But short of that, a
> pageflip needs to trigger a full-plane update, with no dirtyfb
> required.

For per-plane dirty property patches, which ones do you refer to?

Then for xorg, there's my second attempt on fixing the command mode
rotation at [0]. Not sure if that's enough for a fix?

It seems not very efficient to me and I don't really know where
the the per crtc dirty flag should be stored..

I can easily test patches though with a command mode LCD and normal
HDMI setup on droid 4.

Regards,

Tony

[0] https://lists.x.org/archives/xorg-devel/2018-February/055890.html
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Daniel Stone April 20, 2018, 2:39 p.m. UTC | #5

Hi Tony!

On 20 April 2018 at 15:25, Tony Lindgren <[e-mail]> wrote:
> * Daniel Stone <[e-mail]> [180420 10:21]:
>> On 20 April 2018 at 08:09, Tomi Valkeinen <[e-mail]> wrote:
>> > It's actually not quite clear to me how manual update displays work with
>> > DRM...
>> >
>> > As far as I see, we have essentially two cases: 1) single buffering,
>> > where the userspace must set an area in the fb dirty, which then
>> > triggers the update, 2) multi buffering, which doesn't need fb dirty,
>> > but just a page flip which triggers the update.
>> >
>> > In the 2) case (which I think is the optimal case which all the modern
>> > apps should use), there's no need for delayed work or any work, and the
>> > code flow should be very similar to the auto-update model.
>>
>> Correct. There's been talk (and I think patches?) of adding a
>> per-plane dirty property, so userspace can as an optimisation inform
>> the kernel of the area changed between frames. But short of that, a
>> pageflip needs to trigger a full-plane update, with no dirtyfb
>> required.
>
> For per-plane dirty property patches, which ones do you refer to?

Here's the latest iteration of that series:
https://lists.freedesktop.org/archives/dri-devel/2018-April/171900.html
<[e-mail]>

> Then for xorg, there's my second attempt on fixing the command mode
> rotation at [0]. Not sure if that's enough for a fix?
>
> It seems not very efficient to me and I don't really know where
> the the per crtc dirty flag should be stored..

I try to deny all knowledge of X11 these days, I'm afraid.

Cheers,
Daniel
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Tony Lindgren April 20, 2018, 2:44 p.m. UTC | #6

* Daniel Stone <[e-mail]> [180420 14:41]:
> Hi Tony!
> 
> On 20 April 2018 at 15:25, Tony Lindgren <[e-mail]> wrote:
> > * Daniel Stone <[e-mail]> [180420 10:21]:
> >> On 20 April 2018 at 08:09, Tomi Valkeinen <[e-mail]> wrote:
> >> > It's actually not quite clear to me how manual update displays work with
> >> > DRM...
> >> >
> >> > As far as I see, we have essentially two cases: 1) single buffering,
> >> > where the userspace must set an area in the fb dirty, which then
> >> > triggers the update, 2) multi buffering, which doesn't need fb dirty,
> >> > but just a page flip which triggers the update.
> >> >
> >> > In the 2) case (which I think is the optimal case which all the modern
> >> > apps should use), there's no need for delayed work or any work, and the
> >> > code flow should be very similar to the auto-update model.
> >>
> >> Correct. There's been talk (and I think patches?) of adding a
> >> per-plane dirty property, so userspace can as an optimisation inform
> >> the kernel of the area changed between frames. But short of that, a
> >> pageflip needs to trigger a full-plane update, with no dirtyfb
> >> required.
> >
> > For per-plane dirty property patches, which ones do you refer to?
> 
> Here's the latest iteration of that series:
> https://lists.freedesktop.org/archives/dri-devel/2018-April/171900.html
> <[e-mail]>

OK thanks for the link.

> > Then for xorg, there's my second attempt on fixing the command mode
> > rotation at [0]. Not sure if that's enough for a fix?
> >
> > It seems not very efficient to me and I don't really know where
> > the the per crtc dirty flag should be stored..
> 
> I try to deny all knowledge of X11 these days, I'm afraid.

:)

Tony
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Patch

diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
index b893985e4efb..1b91bff5bac6 100644
--- a/drivers/gpu/drm/omapdrm/omap_crtc.c
+++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
@@ -51,6 +51,7 @@  struct omap_crtc {
 	bool pending;
 	wait_queue_head_t pending_wait;
 	struct drm_pending_vblank_event *event;
+	struct delayed_work update_work;
 
 	void (*framedone_handler)(void *);
 	void *framedone_handler_data;
@@ -146,6 +147,25 @@  static void omap_crtc_dss_disconnect(struct omap_drm_private *priv,
 static void omap_crtc_dss_start_update(struct omap_drm_private *priv,
 				       enum omap_channel channel)
 {
+	priv->dispc_ops->mgr_enable(priv->dispc, channel, true);
+}
+
+static bool omap_crtc_is_manually_updated(struct drm_crtc *crtc)
+{
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+	bool result = false;
+
+	drm_connector_list_iter_begin(crtc->dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		if (connector->state->crtc != crtc)
+			continue;
+		result = omap_connector_get_manually_updated(connector);
+		break;
+	}
+	drm_connector_list_iter_end(&conn_iter);
+
+	return result;
 }
 
 /* Called only from the encoder enable/disable and suspend/resume handlers. */
@@ -157,12 +177,17 @@  static void omap_crtc_set_enabled(struct drm_crtc *crtc, bool enable)
 	enum omap_channel channel = omap_crtc->channel;
 	struct omap_irq_wait *wait;
 	u32 framedone_irq, vsync_irq;
+	bool is_manual = omap_crtc_is_manually_updated(crtc);
+	enum omap_display_type type = omap_crtc_output[channel]->output_type;
 	int ret;
 
 	if (WARN_ON(omap_crtc->enabled == enable))
 		return;
 
-	if (omap_crtc_output[channel]->output_type == OMAP_DISPLAY_TYPE_HDMI) {
+	if (is_manual)
+		omap_irq_enable_framedone(crtc, enable);
+
+	if (is_manual || type == OMAP_DISPLAY_TYPE_HDMI) {
 		priv->dispc_ops->mgr_enable(priv->dispc, channel, enable);
 		omap_crtc->enabled = enable;
 		return;
@@ -214,7 +239,6 @@  static void omap_crtc_set_enabled(struct drm_crtc *crtc, bool enable)
 	}
 }
 
-
 static int omap_crtc_dss_enable(struct omap_drm_private *priv,
 				enum omap_channel channel)
 {
@@ -378,6 +402,53 @@  void omap_crtc_framedone_irq(struct drm_crtc *crtc, uint32_t irqstatus)
 	wake_up(&omap_crtc->pending_wait);
 }
 
+void omap_crtc_flush(struct drm_crtc *crtc)
+{
+	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
+
+	if (!omap_crtc_is_manually_updated(crtc))
+		return;
+
+	if (!delayed_work_pending(&omap_crtc->update_work))
+		schedule_delayed_work(&omap_crtc->update_work, 0);
+}
+
+static void omap_crtc_manual_display_update(struct work_struct *data)
+{
+	struct omap_crtc *omap_crtc =
+			container_of(data, struct omap_crtc, update_work.work);
+	struct omap_dss_device *dssdev = omap_crtc_output[omap_crtc->channel];
+	struct drm_device *dev = omap_crtc->base.dev;
+	struct omap_dss_driver *dssdrv;
+	int ret, width, height;
+
+	if (!dssdev || !dssdev->dst) {
+		dev_err_once(dev->dev, "missing dssdev!");
+		return;
+	}
+
+	dssdev = dssdev->dst;
+	dssdrv = dssdev->driver;
+
+	if (!dssdrv || !dssdrv->update) {
+		dev_err_once(dev->dev, "incorrect dssdrv!");
+		return;
+	}
+
+	if (dssdrv->sync)
+		dssdrv->sync(dssdev);
+
+	width = dssdev->panel.vm.hactive;
+	height = dssdev->panel.vm.vactive;
+	ret = dssdrv->update(dssdev, 0, 0, width, height);
+	if (ret < 0) {
+		spin_lock_irq(&dev->event_lock);
+		omap_crtc->pending = false;
+		spin_unlock_irq(&dev->event_lock);
+		wake_up(&omap_crtc->pending_wait);
+	}
+}
+
 static void omap_crtc_write_crtc_properties(struct drm_crtc *crtc)
 {
 	struct omap_drm_private *priv = crtc->dev->dev_private;
@@ -430,6 +501,10 @@  static void omap_crtc_atomic_enable(struct drm_crtc *crtc,
 
 	DBG("%s", omap_crtc->name);
 
+	/* manual updated display will not trigger vsync irq */
+	if (omap_crtc_is_manually_updated(crtc))
+		return;
+
 	spin_lock_irq(&crtc->dev->event_lock);
 	drm_crtc_vblank_on(crtc);
 	ret = drm_crtc_vblank_get(crtc);
@@ -443,6 +518,7 @@  static void omap_crtc_atomic_disable(struct drm_crtc *crtc,
 				     struct drm_crtc_state *old_state)
 {
 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
 
 	DBG("%s", omap_crtc->name);
 
@@ -453,6 +529,11 @@  static void omap_crtc_atomic_disable(struct drm_crtc *crtc,
 	}
 	spin_unlock_irq(&crtc->dev->event_lock);
 
+	cancel_delayed_work(&omap_crtc->update_work);
+
+	if (!omap_crtc_wait_pending(crtc))
+		dev_warn(dev->dev, "manual display update did not finish!");
+
 	drm_crtc_vblank_off(crtc);
 }
 
@@ -603,13 +684,20 @@  static void omap_crtc_atomic_flush(struct drm_crtc *crtc,
 
 	DBG("%s: GO", omap_crtc->name);
 
-	ret = drm_crtc_vblank_get(crtc);
-	WARN_ON(ret != 0);
+	if (!omap_crtc_is_manually_updated(crtc)) {
+		ret = drm_crtc_vblank_get(crtc);
+		WARN_ON(ret != 0);
 
-	spin_lock_irq(&crtc->dev->event_lock);
-	priv->dispc_ops->mgr_go(priv->dispc, omap_crtc->channel);
-	omap_crtc_arm_event(crtc);
-	spin_unlock_irq(&crtc->dev->event_lock);
+		spin_lock_irq(&crtc->dev->event_lock);
+		priv->dispc_ops->mgr_go(priv->dispc, omap_crtc->channel);
+		omap_crtc_arm_event(crtc);
+		spin_unlock_irq(&crtc->dev->event_lock);
+	} else {
+		spin_lock_irq(&crtc->dev->event_lock);
+		omap_crtc_flush(crtc);
+		omap_crtc_arm_event(crtc);
+		spin_unlock_irq(&crtc->dev->event_lock);
+	}
 }
 
 static int omap_crtc_atomic_set_property(struct drm_crtc *crtc,
@@ -771,6 +859,9 @@  struct drm_crtc *omap_crtc_init(struct drm_device *dev,
 	omap_crtc->channel = channel;
 	omap_crtc->name = channel_names[channel];
 
+	INIT_DELAYED_WORK(&omap_crtc->update_work,
+			  omap_crtc_manual_display_update);
+
 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
 					&omap_crtc_funcs, NULL);
 	if (ret < 0) {
diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.h b/drivers/gpu/drm/omapdrm/omap_crtc.h
index c748adc91665..300b6498d03e 100644
--- a/drivers/gpu/drm/omapdrm/omap_crtc.h
+++ b/drivers/gpu/drm/omapdrm/omap_crtc.h
@@ -40,5 +40,6 @@  int omap_crtc_wait_pending(struct drm_crtc *crtc);
 void omap_crtc_error_irq(struct drm_crtc *crtc, u32 irqstatus);
 void omap_crtc_vblank_irq(struct drm_crtc *crtc);
 void omap_crtc_framedone_irq(struct drm_crtc *crtc, uint32_t irqstatus);
+void omap_crtc_flush(struct drm_crtc *crtc);
 
 #endif /* __OMAPDRM_CRTC_H__ */
diff --git a/drivers/gpu/drm/omapdrm/omap_fb.c b/drivers/gpu/drm/omapdrm/omap_fb.c
index 5fd22ca73913..b65212c9a423 100644
--- a/drivers/gpu/drm/omapdrm/omap_fb.c
+++ b/drivers/gpu/drm/omapdrm/omap_fb.c
@@ -95,8 +95,28 @@  static void omap_framebuffer_destroy(struct drm_framebuffer *fb)
 	kfree(omap_fb);
 }
 
+static int omap_framebuffer_dirty(struct drm_framebuffer *fb,
+				  struct drm_file *file_priv,
+				  unsigned flags, unsigned color,
+				  struct drm_clip_rect *clips,
+				  unsigned num_clips)
+{
+	struct drm_connector *connector = NULL;
+
+	drm_modeset_lock_all(fb->dev);
+
+	while ((connector = omap_framebuffer_get_next_connector(fb, connector)))
+		if (connector->encoder && connector->encoder->crtc)
+			omap_crtc_flush(connector->encoder->crtc);
+
+	drm_modeset_unlock_all(fb->dev);
+
+	return 0;
+}
+
 static const struct drm_framebuffer_funcs omap_framebuffer_funcs = {
 	.create_handle = omap_framebuffer_create_handle,
+	.dirty = omap_framebuffer_dirty,
 	.destroy = omap_framebuffer_destroy,
 };