diff mbox

[4/6] drm/dp: Introduce DP MST topology manager state to track DP link bw

Message ID 1483477311-3511-5-git-send-email-dhinakaran.pandiyan@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dhinakaran Pandiyan Jan. 3, 2017, 9:01 p.m. UTC
Link bandwidth is shared between multiple display streams in DP MST
configurations. The DP MST topology manager structure maintains the shared
link bandwidth for a primary link directly connected to the GPU. For atomic
modesetting drivers, checking if there is sufficient link bandwidth for a
mode needs to be done during the atomic_check phase to avoid failed
modesets. Let's encsapsulate the available link bw information in a state
structure so that bw can be allocated and released atomically for each of
the ports sharing the primary link.

Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
---
 drivers/gpu/drm/drm_atomic.c          | 66 +++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_atomic_helper.c   | 10 ++++++
 drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++
 include/drm/drm_atomic.h              | 13 +++++++
 include/drm/drm_dp_mst_helper.h       | 13 +++++++
 5 files changed, 112 insertions(+)

Comments

Daniel Vetter Jan. 4, 2017, 9:33 a.m. UTC | #1
On Tue, Jan 03, 2017 at 01:01:49PM -0800, Dhinakaran Pandiyan wrote:
> Link bandwidth is shared between multiple display streams in DP MST
> configurations. The DP MST topology manager structure maintains the shared
> link bandwidth for a primary link directly connected to the GPU. For atomic
> modesetting drivers, checking if there is sufficient link bandwidth for a
> mode needs to be done during the atomic_check phase to avoid failed
> modesets. Let's encsapsulate the available link bw information in a state
> structure so that bw can be allocated and released atomically for each of
> the ports sharing the primary link.
> 
> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>

Overall issue with the patch is that dp helpers now have 2 places where
available_slots is stored: One for atomic drivers in ->state, and the
legacy one. I think it'd be good to rework the legacy codepaths (i.e.
drm_dp_find_vcpi_slots) to use mgr->state->avail_slots, and remove
mgr->avail_slots entirely.

Another design concern below, but in principle this looks like what we
need.
-Daniel


> ---
>  drivers/gpu/drm/drm_atomic.c          | 66 +++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_atomic_helper.c   | 10 ++++++
>  drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++
>  include/drm/drm_atomic.h              | 13 +++++++
>  include/drm/drm_dp_mst_helper.h       | 13 +++++++
>  5 files changed, 112 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 681d5f9..b8e2cea 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -31,6 +31,7 @@
>  #include <drm/drm_mode.h>
>  #include <drm/drm_plane_helper.h>
>  #include <drm/drm_print.h>
> +#include <drm/drm_dp_mst_helper.h>
>  #include <linux/sync_file.h>
>  
>  #include "drm_crtc_internal.h"
> @@ -62,6 +63,7 @@ void drm_atomic_state_default_release(struct drm_atomic_state *state)
>  	kfree(state->connectors);
>  	kfree(state->crtcs);
>  	kfree(state->planes);
> +	kfree(state->dp_mst_topologies);
>  }
>  EXPORT_SYMBOL(drm_atomic_state_default_release);
>  
> @@ -189,6 +191,18 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
>  		state->planes[i].ptr = NULL;
>  		state->planes[i].state = NULL;
>  	}
> +
> +	for (i = 0; i < state->num_mst_topologies; i++) {
> +		struct drm_dp_mst_topology_mgr *mgr = state->dp_mst_topologies[i].ptr;
> +
> +		if (!mgr)
> +			continue;
> +
> +		kfree(state->dp_mst_topologies[i].state);
> +		state->dp_mst_topologies[i].ptr = NULL;
> +		state->dp_mst_topologies[i].state = NULL;
> +	}
> +
>  }
>  EXPORT_SYMBOL(drm_atomic_state_default_clear);
>  
> @@ -981,6 +995,58 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,
>  		plane->funcs->atomic_print_state(p, state);
>  }
>  
> +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> +		struct drm_dp_mst_topology_mgr *mgr)
> +{
> +
> +	int ret, i;
> +	size_t new_size;
> +	struct __drm_dp_mst_topology_state *new_arr;
> +	struct drm_dp_mst_topology_state *new_mst_state;
> +	int num_topologies;
> +	struct drm_mode_config *config = &mgr->dev->mode_config;
> +
> +	WARN_ON(!state->acquire_ctx);
> +
> +	ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	for (i = 0; i < state->num_mst_topologies; i++) {
> +		if (mgr == state->dp_mst_topologies[i].ptr &&
> +		    state->dp_mst_topologies[i].state) {
> +			return state->dp_mst_topologies[i].state;
> +		}
> +	}
> +
> +	num_topologies = state->num_mst_topologies + 1;
> +	new_size = sizeof(*state->dp_mst_topologies) * num_topologies;
> +	new_arr = krealloc(state->dp_mst_topologies, new_size, GFP_KERNEL);
> +	if (!new_arr)
> +		return ERR_PTR(-ENOMEM);
> +
> +	state->dp_mst_topologies = new_arr;
> +	memset(&state->dp_mst_topologies[state->num_mst_topologies], 0,
> +		sizeof(*state->dp_mst_topologies));
> +
> +	new_mst_state = kmalloc(sizeof(*mgr->state), GFP_KERNEL);
> +	if (!new_mst_state)
> +		return ERR_PTR(-ENOMEM);
> +
> +	new_mst_state->avail_slots = mgr->state->avail_slots;
> +	state->dp_mst_topologies[state->num_mst_topologies].state = new_mst_state;
> +	state->dp_mst_topologies[state->num_mst_topologies].ptr = mgr;
> +	state->num_mst_topologies = num_topologies;
> +	new_mst_state->mgr = mgr;
> +	mgr->state->state = state;
> +
> +	DRM_DEBUG_ATOMIC("Added [MST Topology w/ base connector:%d] %p state to %p\n",
> +			 mgr->conn_base_id, new_mst_state, state);
> +
> +	return new_mst_state;
> +}
> +EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
> +
>  /**
>   * drm_atomic_get_connector_state - get connector state
>   * @state: global atomic state object
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 5e52244..1cd38b7 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -30,6 +30,7 @@
>  #include <drm/drm_plane_helper.h>
>  #include <drm/drm_crtc_helper.h>
>  #include <drm/drm_atomic_helper.h>
> +#include <drm/drm_dp_mst_helper.h>
>  #include <linux/dma-fence.h>
>  
>  #include "drm_crtc_internal.h"
> @@ -1992,6 +1993,15 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
>  		connector->state->state = NULL;
>  	}
>  
> +	for (i = 0; i < state->num_mst_topologies; i++) {
> +		struct drm_dp_mst_topology_mgr *mgr;
> +
> +		mgr = state->dp_mst_topologies[i].ptr;
> +		mgr->state->state = state;
> +		swap(state->dp_mst_topologies[i].state, mgr->state);
> +		mgr->state->state = NULL;
> +	}

I'm not sure we want to tie the dp mst helpers that closely with the
atomic machinery, otoh it makes things a lot easier. My concern is that
drm_atomic_state is a core structure, whereas the dp_mst stuff is a
helper, which means we have a control inversion here compared to the
normal pattern.

> +
>  	for_each_crtc_in_state(state, crtc, crtc_state, i) {
>  		crtc->state->state = state;
>  		swap(state->crtcs[i].state, crtc->state);
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index d42a6c0..1be19e1 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -2042,6 +2042,9 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
>  			goto out_unlock;
>  		}
>  
> +		/* max. time slots - one slot for MTP header */
> +		mgr->state->avail_slots = 63;
> +
>  		/* add initial branch device at LCT 1 */
>  		mstb = drm_dp_add_mst_branch_device(1, NULL);
>  		if (mstb == NULL) {
> @@ -2973,6 +2976,11 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
>  	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
>  	if (!mgr->proposed_vcpis)
>  		return -ENOMEM;
> +	mgr->state = kzalloc(sizeof(*mgr->state), GFP_KERNEL);
> +	if (!mgr->state)
> +		return -ENOMEM;
> +	mgr->state->mgr = mgr;
> +
>  	set_bit(0, &mgr->payload_mask);
>  	if (test_calc_pbn_mode() < 0)
>  		DRM_ERROR("MST PBN self-test failed\n");
> @@ -2995,6 +3003,8 @@ void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
>  	kfree(mgr->proposed_vcpis);
>  	mgr->proposed_vcpis = NULL;
>  	mutex_unlock(&mgr->payload_lock);
> +	kfree(mgr->state);
> +	mgr->state = NULL;
>  	mgr->dev = NULL;
>  	mgr->aux = NULL;
>  }
> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> index fd2d971..7ac5ed6 100644
> --- a/include/drm/drm_atomic.h
> +++ b/include/drm/drm_atomic.h
> @@ -153,6 +153,11 @@ struct __drm_connnectors_state {
>  	struct drm_connector_state *state;
>  };
>  
> +struct __drm_dp_mst_topology_state {
> +	struct drm_dp_mst_topology_mgr *ptr;
> +	struct drm_dp_mst_topology_state *state;

One way to fix that control inversion I mentioned above is to use void*
pionters here, and then have callbacks for atomic_destroy and swap_state
on top. A bit more shuffling, but we could then use that for other driver
private objects.

Other option is to stuff it into intel_atomic_state.

> +};
> +
>  /**
>   * struct drm_atomic_state - the global state object for atomic updates
>   * @ref: count of all references to this state (will not be freed until zero)
> @@ -164,6 +169,8 @@ struct __drm_connnectors_state {
>   * @crtcs: pointer to array of CRTC pointers
>   * @num_connector: size of the @connectors and @connector_states arrays
>   * @connectors: pointer to array of structures with per-connector data
> + * @num_mst_topologies: size of the @dp_mst_topologies array
> + * @dp_mst_topologies: pointer to array of structures with per-MST topology manager data
>   * @acquire_ctx: acquire context for this atomic modeset state update
>   */
>  struct drm_atomic_state {
> @@ -177,6 +184,8 @@ struct drm_atomic_state {
>  	struct __drm_crtcs_state *crtcs;
>  	int num_connector;
>  	struct __drm_connnectors_state *connectors;
> +	int num_mst_topologies;
> +	struct __drm_dp_mst_topology_state *dp_mst_topologies;
>  
>  	struct drm_modeset_acquire_ctx *acquire_ctx;
>  
> @@ -250,6 +259,10 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
>  		struct drm_connector_state *state, struct drm_property *property,
>  		uint64_t val);
>  
> +struct drm_dp_mst_topology_state * __must_check
> +drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> +				  struct drm_dp_mst_topology_mgr *mgr);
> +
>  /**
>   * drm_atomic_get_existing_crtc_state - get crtc state, if it exists
>   * @state: global atomic state object
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index 98d3c73..0a9bf20 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -403,6 +403,12 @@ struct drm_dp_payload {
>  	int vcpi;
>  };
>  
> +struct drm_dp_mst_topology_state {
> +	int avail_slots;
> +	struct drm_atomic_state *state;
> +	struct drm_dp_mst_topology_mgr *mgr;
> +};
> +
>  /**
>   * struct drm_dp_mst_topology_mgr - DisplayPort MST manager
>   *
> @@ -481,6 +487,11 @@ struct drm_dp_mst_topology_mgr {
>  	int pbn_div;
>  
>  	/**
> +	 *  @state: MST topology manager state for atomic modesetting drivers
> +	 */
> +	struct drm_dp_mst_topology_state *state;
> +
> +	/**
>  	 * @qlock: protects @tx_msg_downq, the tx_slots in struct
>  	 * &drm_dp_mst_branch and txmsg->state once they are queued
>  	 */
> @@ -596,4 +607,6 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
>  
>  void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
>  int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
> +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> +					struct drm_dp_mst_topology_mgr *mgr);
>  #endif
> -- 
> 2.7.4
>
Dhinakaran Pandiyan Jan. 4, 2017, 7:20 p.m. UTC | #2
On Wed, 2017-01-04 at 10:33 +0100, Daniel Vetter wrote:
> On Tue, Jan 03, 2017 at 01:01:49PM -0800, Dhinakaran Pandiyan wrote:

> > Link bandwidth is shared between multiple display streams in DP MST

> > configurations. The DP MST topology manager structure maintains the shared

> > link bandwidth for a primary link directly connected to the GPU. For atomic

> > modesetting drivers, checking if there is sufficient link bandwidth for a

> > mode needs to be done during the atomic_check phase to avoid failed

> > modesets. Let's encsapsulate the available link bw information in a state

> > structure so that bw can be allocated and released atomically for each of

> > the ports sharing the primary link.

> > 

> > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>

> 

> Overall issue with the patch is that dp helpers now have 2 places where

> available_slots is stored: One for atomic drivers in ->state, and the

> legacy one. I think it'd be good to rework the legacy codepaths (i.e.

> drm_dp_find_vcpi_slots) to use mgr->state->avail_slots, and remove

> mgr->avail_slots entirely.


PATCH 2/6 does that. mgr->avail_slots is not updated in the legacy code
path, so the check turns out to be against mgr->total_slots. So, I did
just that, albeit explicitly. 

-DK

> 

> Another design concern below, but in principle this looks like what we

> need.

> -Daniel

> 

> 

> > ---

> >  drivers/gpu/drm/drm_atomic.c          | 66 +++++++++++++++++++++++++++++++++++

> >  drivers/gpu/drm/drm_atomic_helper.c   | 10 ++++++

> >  drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++

> >  include/drm/drm_atomic.h              | 13 +++++++

> >  include/drm/drm_dp_mst_helper.h       | 13 +++++++

> >  5 files changed, 112 insertions(+)

> > 

> > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c

> > index 681d5f9..b8e2cea 100644

> > --- a/drivers/gpu/drm/drm_atomic.c

> > +++ b/drivers/gpu/drm/drm_atomic.c

> > @@ -31,6 +31,7 @@

> >  #include <drm/drm_mode.h>

> >  #include <drm/drm_plane_helper.h>

> >  #include <drm/drm_print.h>

> > +#include <drm/drm_dp_mst_helper.h>

> >  #include <linux/sync_file.h>

> >  

> >  #include "drm_crtc_internal.h"

> > @@ -62,6 +63,7 @@ void drm_atomic_state_default_release(struct drm_atomic_state *state)

> >  	kfree(state->connectors);

> >  	kfree(state->crtcs);

> >  	kfree(state->planes);

> > +	kfree(state->dp_mst_topologies);

> >  }

> >  EXPORT_SYMBOL(drm_atomic_state_default_release);

> >  

> > @@ -189,6 +191,18 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)

> >  		state->planes[i].ptr = NULL;

> >  		state->planes[i].state = NULL;

> >  	}

> > +

> > +	for (i = 0; i < state->num_mst_topologies; i++) {

> > +		struct drm_dp_mst_topology_mgr *mgr = state->dp_mst_topologies[i].ptr;

> > +

> > +		if (!mgr)

> > +			continue;

> > +

> > +		kfree(state->dp_mst_topologies[i].state);

> > +		state->dp_mst_topologies[i].ptr = NULL;

> > +		state->dp_mst_topologies[i].state = NULL;

> > +	}

> > +

> >  }

> >  EXPORT_SYMBOL(drm_atomic_state_default_clear);

> >  

> > @@ -981,6 +995,58 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,

> >  		plane->funcs->atomic_print_state(p, state);

> >  }

> >  

> > +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,

> > +		struct drm_dp_mst_topology_mgr *mgr)

> > +{

> > +

> > +	int ret, i;

> > +	size_t new_size;

> > +	struct __drm_dp_mst_topology_state *new_arr;

> > +	struct drm_dp_mst_topology_state *new_mst_state;

> > +	int num_topologies;

> > +	struct drm_mode_config *config = &mgr->dev->mode_config;

> > +

> > +	WARN_ON(!state->acquire_ctx);

> > +

> > +	ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);

> > +	if (ret)

> > +		return ERR_PTR(ret);

> > +

> > +	for (i = 0; i < state->num_mst_topologies; i++) {

> > +		if (mgr == state->dp_mst_topologies[i].ptr &&

> > +		    state->dp_mst_topologies[i].state) {

> > +			return state->dp_mst_topologies[i].state;

> > +		}

> > +	}

> > +

> > +	num_topologies = state->num_mst_topologies + 1;

> > +	new_size = sizeof(*state->dp_mst_topologies) * num_topologies;

> > +	new_arr = krealloc(state->dp_mst_topologies, new_size, GFP_KERNEL);

> > +	if (!new_arr)

> > +		return ERR_PTR(-ENOMEM);

> > +

> > +	state->dp_mst_topologies = new_arr;

> > +	memset(&state->dp_mst_topologies[state->num_mst_topologies], 0,

> > +		sizeof(*state->dp_mst_topologies));

> > +

> > +	new_mst_state = kmalloc(sizeof(*mgr->state), GFP_KERNEL);

> > +	if (!new_mst_state)

> > +		return ERR_PTR(-ENOMEM);

> > +

> > +	new_mst_state->avail_slots = mgr->state->avail_slots;

> > +	state->dp_mst_topologies[state->num_mst_topologies].state = new_mst_state;

> > +	state->dp_mst_topologies[state->num_mst_topologies].ptr = mgr;

> > +	state->num_mst_topologies = num_topologies;

> > +	new_mst_state->mgr = mgr;

> > +	mgr->state->state = state;

> > +

> > +	DRM_DEBUG_ATOMIC("Added [MST Topology w/ base connector:%d] %p state to %p\n",

> > +			 mgr->conn_base_id, new_mst_state, state);

> > +

> > +	return new_mst_state;

> > +}

> > +EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);

> > +

> >  /**

> >   * drm_atomic_get_connector_state - get connector state

> >   * @state: global atomic state object

> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c

> > index 5e52244..1cd38b7 100644

> > --- a/drivers/gpu/drm/drm_atomic_helper.c

> > +++ b/drivers/gpu/drm/drm_atomic_helper.c

> > @@ -30,6 +30,7 @@

> >  #include <drm/drm_plane_helper.h>

> >  #include <drm/drm_crtc_helper.h>

> >  #include <drm/drm_atomic_helper.h>

> > +#include <drm/drm_dp_mst_helper.h>

> >  #include <linux/dma-fence.h>

> >  

> >  #include "drm_crtc_internal.h"

> > @@ -1992,6 +1993,15 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state,

> >  		connector->state->state = NULL;

> >  	}

> >  

> > +	for (i = 0; i < state->num_mst_topologies; i++) {

> > +		struct drm_dp_mst_topology_mgr *mgr;

> > +

> > +		mgr = state->dp_mst_topologies[i].ptr;

> > +		mgr->state->state = state;

> > +		swap(state->dp_mst_topologies[i].state, mgr->state);

> > +		mgr->state->state = NULL;

> > +	}

> 

> I'm not sure we want to tie the dp mst helpers that closely with the

> atomic machinery, otoh it makes things a lot easier. My concern is that

> drm_atomic_state is a core structure, whereas the dp_mst stuff is a

> helper, which means we have a control inversion here compared to the

> normal pattern.

> 

> > +

> >  	for_each_crtc_in_state(state, crtc, crtc_state, i) {

> >  		crtc->state->state = state;

> >  		swap(state->crtcs[i].state, crtc->state);

> > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c

> > index d42a6c0..1be19e1 100644

> > --- a/drivers/gpu/drm/drm_dp_mst_topology.c

> > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c

> > @@ -2042,6 +2042,9 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms

> >  			goto out_unlock;

> >  		}

> >  

> > +		/* max. time slots - one slot for MTP header */

> > +		mgr->state->avail_slots = 63;

> > +

> >  		/* add initial branch device at LCT 1 */

> >  		mstb = drm_dp_add_mst_branch_device(1, NULL);

> >  		if (mstb == NULL) {

> > @@ -2973,6 +2976,11 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,

> >  	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);

> >  	if (!mgr->proposed_vcpis)

> >  		return -ENOMEM;

> > +	mgr->state = kzalloc(sizeof(*mgr->state), GFP_KERNEL);

> > +	if (!mgr->state)

> > +		return -ENOMEM;

> > +	mgr->state->mgr = mgr;

> > +

> >  	set_bit(0, &mgr->payload_mask);

> >  	if (test_calc_pbn_mode() < 0)

> >  		DRM_ERROR("MST PBN self-test failed\n");

> > @@ -2995,6 +3003,8 @@ void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)

> >  	kfree(mgr->proposed_vcpis);

> >  	mgr->proposed_vcpis = NULL;

> >  	mutex_unlock(&mgr->payload_lock);

> > +	kfree(mgr->state);

> > +	mgr->state = NULL;

> >  	mgr->dev = NULL;

> >  	mgr->aux = NULL;

> >  }

> > diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h

> > index fd2d971..7ac5ed6 100644

> > --- a/include/drm/drm_atomic.h

> > +++ b/include/drm/drm_atomic.h

> > @@ -153,6 +153,11 @@ struct __drm_connnectors_state {

> >  	struct drm_connector_state *state;

> >  };

> >  

> > +struct __drm_dp_mst_topology_state {

> > +	struct drm_dp_mst_topology_mgr *ptr;

> > +	struct drm_dp_mst_topology_state *state;

> 

> One way to fix that control inversion I mentioned above is to use void*

> pionters here, and then have callbacks for atomic_destroy and swap_state

> on top. A bit more shuffling, but we could then use that for other driver

> private objects.

> 

> Other option is to stuff it into intel_atomic_state.

> 

> > +};

> > +

> >  /**

> >   * struct drm_atomic_state - the global state object for atomic updates

> >   * @ref: count of all references to this state (will not be freed until zero)

> > @@ -164,6 +169,8 @@ struct __drm_connnectors_state {

> >   * @crtcs: pointer to array of CRTC pointers

> >   * @num_connector: size of the @connectors and @connector_states arrays

> >   * @connectors: pointer to array of structures with per-connector data

> > + * @num_mst_topologies: size of the @dp_mst_topologies array

> > + * @dp_mst_topologies: pointer to array of structures with per-MST topology manager data

> >   * @acquire_ctx: acquire context for this atomic modeset state update

> >   */

> >  struct drm_atomic_state {

> > @@ -177,6 +184,8 @@ struct drm_atomic_state {

> >  	struct __drm_crtcs_state *crtcs;

> >  	int num_connector;

> >  	struct __drm_connnectors_state *connectors;

> > +	int num_mst_topologies;

> > +	struct __drm_dp_mst_topology_state *dp_mst_topologies;

> >  

> >  	struct drm_modeset_acquire_ctx *acquire_ctx;

> >  

> > @@ -250,6 +259,10 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,

> >  		struct drm_connector_state *state, struct drm_property *property,

> >  		uint64_t val);

> >  

> > +struct drm_dp_mst_topology_state * __must_check

> > +drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,

> > +				  struct drm_dp_mst_topology_mgr *mgr);

> > +

> >  /**

> >   * drm_atomic_get_existing_crtc_state - get crtc state, if it exists

> >   * @state: global atomic state object

> > diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h

> > index 98d3c73..0a9bf20 100644

> > --- a/include/drm/drm_dp_mst_helper.h

> > +++ b/include/drm/drm_dp_mst_helper.h

> > @@ -403,6 +403,12 @@ struct drm_dp_payload {

> >  	int vcpi;

> >  };

> >  

> > +struct drm_dp_mst_topology_state {

> > +	int avail_slots;

> > +	struct drm_atomic_state *state;

> > +	struct drm_dp_mst_topology_mgr *mgr;

> > +};

> > +

> >  /**

> >   * struct drm_dp_mst_topology_mgr - DisplayPort MST manager

> >   *

> > @@ -481,6 +487,11 @@ struct drm_dp_mst_topology_mgr {

> >  	int pbn_div;

> >  

> >  	/**

> > +	 *  @state: MST topology manager state for atomic modesetting drivers

> > +	 */

> > +	struct drm_dp_mst_topology_state *state;

> > +

> > +	/**

> >  	 * @qlock: protects @tx_msg_downq, the tx_slots in struct

> >  	 * &drm_dp_mst_branch and txmsg->state once they are queued

> >  	 */

> > @@ -596,4 +607,6 @@ void drm_dp_mst_dump_topology(struct seq_file *m,

> >  

> >  void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);

> >  int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);

> > +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,

> > +					struct drm_dp_mst_topology_mgr *mgr);

> >  #endif

> > -- 

> > 2.7.4

> > 

>
Dhinakaran Pandiyan Jan. 5, 2017, 3:54 a.m. UTC | #3
On Wed, 2017-01-04 at 19:20 +0000, Pandiyan, Dhinakaran wrote:
> On Wed, 2017-01-04 at 10:33 +0100, Daniel Vetter wrote:

> > On Tue, Jan 03, 2017 at 01:01:49PM -0800, Dhinakaran Pandiyan wrote:

> > > Link bandwidth is shared between multiple display streams in DP MST

> > > configurations. The DP MST topology manager structure maintains the shared

> > > link bandwidth for a primary link directly connected to the GPU. For atomic

> > > modesetting drivers, checking if there is sufficient link bandwidth for a

> > > mode needs to be done during the atomic_check phase to avoid failed

> > > modesets. Let's encsapsulate the available link bw information in a state

> > > structure so that bw can be allocated and released atomically for each of

> > > the ports sharing the primary link.

> > > 

> > > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>

> > 

> > Overall issue with the patch is that dp helpers now have 2 places where

> > available_slots is stored: One for atomic drivers in ->state, and the

> > legacy one. I think it'd be good to rework the legacy codepaths (i.e.

> > drm_dp_find_vcpi_slots) to use mgr->state->avail_slots, and remove

> > mgr->avail_slots entirely.

> 

> PATCH 2/6 does that. mgr->avail_slots is not updated in the legacy code

> path, so the check turns out to be against mgr->total_slots. So, I did

> just that, albeit explicitly. 

> 

> -DK

> 

> > 

> > Another design concern below, but in principle this looks like what we

> > need.

> > -Daniel

> > 

> > 

> > > ---

> > >  drivers/gpu/drm/drm_atomic.c          | 66 +++++++++++++++++++++++++++++++++++

> > >  drivers/gpu/drm/drm_atomic_helper.c   | 10 ++++++

> > >  drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++

> > >  include/drm/drm_atomic.h              | 13 +++++++

> > >  include/drm/drm_dp_mst_helper.h       | 13 +++++++

> > >  5 files changed, 112 insertions(+)

> > > 

> > > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c

> > > index 681d5f9..b8e2cea 100644

> > > --- a/drivers/gpu/drm/drm_atomic.c

> > > +++ b/drivers/gpu/drm/drm_atomic.c

> > > @@ -31,6 +31,7 @@

> > >  #include <drm/drm_mode.h>

> > >  #include <drm/drm_plane_helper.h>

> > >  #include <drm/drm_print.h>

> > > +#include <drm/drm_dp_mst_helper.h>

> > >  #include <linux/sync_file.h>

> > >  

> > >  #include "drm_crtc_internal.h"

> > > @@ -62,6 +63,7 @@ void drm_atomic_state_default_release(struct drm_atomic_state *state)

> > >  	kfree(state->connectors);

> > >  	kfree(state->crtcs);

> > >  	kfree(state->planes);

> > > +	kfree(state->dp_mst_topologies);

> > >  }

> > >  EXPORT_SYMBOL(drm_atomic_state_default_release);

> > >  

> > > @@ -189,6 +191,18 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)

> > >  		state->planes[i].ptr = NULL;

> > >  		state->planes[i].state = NULL;

> > >  	}

> > > +

> > > +	for (i = 0; i < state->num_mst_topologies; i++) {

> > > +		struct drm_dp_mst_topology_mgr *mgr = state->dp_mst_topologies[i].ptr;

> > > +

> > > +		if (!mgr)

> > > +			continue;

> > > +

> > > +		kfree(state->dp_mst_topologies[i].state);

> > > +		state->dp_mst_topologies[i].ptr = NULL;

> > > +		state->dp_mst_topologies[i].state = NULL;

> > > +	}

> > > +

> > >  }

> > >  EXPORT_SYMBOL(drm_atomic_state_default_clear);

> > >  

> > > @@ -981,6 +995,58 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,

> > >  		plane->funcs->atomic_print_state(p, state);

> > >  }

> > >  

> > > +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,

> > > +		struct drm_dp_mst_topology_mgr *mgr)

> > > +{

> > > +

> > > +	int ret, i;

> > > +	size_t new_size;

> > > +	struct __drm_dp_mst_topology_state *new_arr;

> > > +	struct drm_dp_mst_topology_state *new_mst_state;

> > > +	int num_topologies;

> > > +	struct drm_mode_config *config = &mgr->dev->mode_config;

> > > +

> > > +	WARN_ON(!state->acquire_ctx);

> > > +

> > > +	ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);

> > > +	if (ret)

> > > +		return ERR_PTR(ret);

> > > +

> > > +	for (i = 0; i < state->num_mst_topologies; i++) {

> > > +		if (mgr == state->dp_mst_topologies[i].ptr &&

> > > +		    state->dp_mst_topologies[i].state) {

> > > +			return state->dp_mst_topologies[i].state;

> > > +		}

> > > +	}

> > > +

> > > +	num_topologies = state->num_mst_topologies + 1;

> > > +	new_size = sizeof(*state->dp_mst_topologies) * num_topologies;

> > > +	new_arr = krealloc(state->dp_mst_topologies, new_size, GFP_KERNEL);

> > > +	if (!new_arr)

> > > +		return ERR_PTR(-ENOMEM);

> > > +

> > > +	state->dp_mst_topologies = new_arr;

> > > +	memset(&state->dp_mst_topologies[state->num_mst_topologies], 0,

> > > +		sizeof(*state->dp_mst_topologies));

> > > +

> > > +	new_mst_state = kmalloc(sizeof(*mgr->state), GFP_KERNEL);

> > > +	if (!new_mst_state)

> > > +		return ERR_PTR(-ENOMEM);

> > > +

> > > +	new_mst_state->avail_slots = mgr->state->avail_slots;

> > > +	state->dp_mst_topologies[state->num_mst_topologies].state = new_mst_state;

> > > +	state->dp_mst_topologies[state->num_mst_topologies].ptr = mgr;

> > > +	state->num_mst_topologies = num_topologies;

> > > +	new_mst_state->mgr = mgr;

> > > +	mgr->state->state = state;

> > > +

> > > +	DRM_DEBUG_ATOMIC("Added [MST Topology w/ base connector:%d] %p state to %p\n",

> > > +			 mgr->conn_base_id, new_mst_state, state);

> > > +

> > > +	return new_mst_state;

> > > +}

> > > +EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);

> > > +

> > >  /**

> > >   * drm_atomic_get_connector_state - get connector state

> > >   * @state: global atomic state object

> > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c

> > > index 5e52244..1cd38b7 100644

> > > --- a/drivers/gpu/drm/drm_atomic_helper.c

> > > +++ b/drivers/gpu/drm/drm_atomic_helper.c

> > > @@ -30,6 +30,7 @@

> > >  #include <drm/drm_plane_helper.h>

> > >  #include <drm/drm_crtc_helper.h>

> > >  #include <drm/drm_atomic_helper.h>

> > > +#include <drm/drm_dp_mst_helper.h>

> > >  #include <linux/dma-fence.h>

> > >  

> > >  #include "drm_crtc_internal.h"

> > > @@ -1992,6 +1993,15 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state,

> > >  		connector->state->state = NULL;

> > >  	}

> > >  

> > > +	for (i = 0; i < state->num_mst_topologies; i++) {

> > > +		struct drm_dp_mst_topology_mgr *mgr;

> > > +

> > > +		mgr = state->dp_mst_topologies[i].ptr;

> > > +		mgr->state->state = state;

> > > +		swap(state->dp_mst_topologies[i].state, mgr->state);

> > > +		mgr->state->state = NULL;

> > > +	}

> > 

> > I'm not sure we want to tie the dp mst helpers that closely with the

> > atomic machinery, otoh it makes things a lot easier. My concern is that

> > drm_atomic_state is a core structure, whereas the dp_mst stuff is a

> > helper, which means we have a control inversion here compared to the

> > normal pattern.

> > 

> > > +

> > >  	for_each_crtc_in_state(state, crtc, crtc_state, i) {

> > >  		crtc->state->state = state;

> > >  		swap(state->crtcs[i].state, crtc->state);

> > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c

> > > index d42a6c0..1be19e1 100644

> > > --- a/drivers/gpu/drm/drm_dp_mst_topology.c

> > > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c

> > > @@ -2042,6 +2042,9 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms

> > >  			goto out_unlock;

> > >  		}

> > >  

> > > +		/* max. time slots - one slot for MTP header */

> > > +		mgr->state->avail_slots = 63;

> > > +

> > >  		/* add initial branch device at LCT 1 */

> > >  		mstb = drm_dp_add_mst_branch_device(1, NULL);

> > >  		if (mstb == NULL) {

> > > @@ -2973,6 +2976,11 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,

> > >  	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);

> > >  	if (!mgr->proposed_vcpis)

> > >  		return -ENOMEM;

> > > +	mgr->state = kzalloc(sizeof(*mgr->state), GFP_KERNEL);

> > > +	if (!mgr->state)

> > > +		return -ENOMEM;

> > > +	mgr->state->mgr = mgr;

> > > +

> > >  	set_bit(0, &mgr->payload_mask);

> > >  	if (test_calc_pbn_mode() < 0)

> > >  		DRM_ERROR("MST PBN self-test failed\n");

> > > @@ -2995,6 +3003,8 @@ void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)

> > >  	kfree(mgr->proposed_vcpis);

> > >  	mgr->proposed_vcpis = NULL;

> > >  	mutex_unlock(&mgr->payload_lock);

> > > +	kfree(mgr->state);

> > > +	mgr->state = NULL;

> > >  	mgr->dev = NULL;

> > >  	mgr->aux = NULL;

> > >  }

> > > diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h

> > > index fd2d971..7ac5ed6 100644

> > > --- a/include/drm/drm_atomic.h

> > > +++ b/include/drm/drm_atomic.h

> > > @@ -153,6 +153,11 @@ struct __drm_connnectors_state {

> > >  	struct drm_connector_state *state;

> > >  };

> > >  

> > > +struct __drm_dp_mst_topology_state {

> > > +	struct drm_dp_mst_topology_mgr *ptr;

> > > +	struct drm_dp_mst_topology_state *state;

> > 

> > One way to fix that control inversion I mentioned above is to use void*

> > pionters here, and then have callbacks for atomic_destroy and swap_state

> > on top. A bit more shuffling, but we could then use that for other driver

> > private objects.

> > 

> > Other option is to stuff it into intel_atomic_state.

> > 


Hmm... I think I understand what you are saying. The core atomic
functions like swap_state should not be able alter the topology
manager's current state?

Did you mean something like this - https://paste.ubuntu.com/23743485/ ?

Do we need the destroy callback too? drm_atomic_state_default_clear()
does not have to dereference drm_dp_mst_topology_mgr.



Moving this to intel_atomic_state would be mean that nouveau will
require a re-implementation. Is that right?


-DK


> > > +};

> > > +

> > >  /**

> > >   * struct drm_atomic_state - the global state object for atomic updates

> > >   * @ref: count of all references to this state (will not be freed until zero)

> > > @@ -164,6 +169,8 @@ struct __drm_connnectors_state {

> > >   * @crtcs: pointer to array of CRTC pointers

> > >   * @num_connector: size of the @connectors and @connector_states arrays

> > >   * @connectors: pointer to array of structures with per-connector data

> > > + * @num_mst_topologies: size of the @dp_mst_topologies array

> > > + * @dp_mst_topologies: pointer to array of structures with per-MST topology manager data

> > >   * @acquire_ctx: acquire context for this atomic modeset state update

> > >   */

> > >  struct drm_atomic_state {

> > > @@ -177,6 +184,8 @@ struct drm_atomic_state {

> > >  	struct __drm_crtcs_state *crtcs;

> > >  	int num_connector;

> > >  	struct __drm_connnectors_state *connectors;

> > > +	int num_mst_topologies;

> > > +	struct __drm_dp_mst_topology_state *dp_mst_topologies;

> > >  

> > >  	struct drm_modeset_acquire_ctx *acquire_ctx;

> > >  

> > > @@ -250,6 +259,10 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,

> > >  		struct drm_connector_state *state, struct drm_property *property,

> > >  		uint64_t val);

> > >  

> > > +struct drm_dp_mst_topology_state * __must_check

> > > +drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,

> > > +				  struct drm_dp_mst_topology_mgr *mgr);

> > > +

> > >  /**

> > >   * drm_atomic_get_existing_crtc_state - get crtc state, if it exists

> > >   * @state: global atomic state object

> > > diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h

> > > index 98d3c73..0a9bf20 100644

> > > --- a/include/drm/drm_dp_mst_helper.h

> > > +++ b/include/drm/drm_dp_mst_helper.h

> > > @@ -403,6 +403,12 @@ struct drm_dp_payload {

> > >  	int vcpi;

> > >  };

> > >  

> > > +struct drm_dp_mst_topology_state {

> > > +	int avail_slots;

> > > +	struct drm_atomic_state *state;

> > > +	struct drm_dp_mst_topology_mgr *mgr;

> > > +};

> > > +

> > >  /**

> > >   * struct drm_dp_mst_topology_mgr - DisplayPort MST manager

> > >   *

> > > @@ -481,6 +487,11 @@ struct drm_dp_mst_topology_mgr {

> > >  	int pbn_div;

> > >  

> > >  	/**

> > > +	 *  @state: MST topology manager state for atomic modesetting drivers

> > > +	 */

> > > +	struct drm_dp_mst_topology_state *state;

> > > +

> > > +	/**

> > >  	 * @qlock: protects @tx_msg_downq, the tx_slots in struct

> > >  	 * &drm_dp_mst_branch and txmsg->state once they are queued

> > >  	 */

> > > @@ -596,4 +607,6 @@ void drm_dp_mst_dump_topology(struct seq_file *m,

> > >  

> > >  void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);

> > >  int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);

> > > +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,

> > > +					struct drm_dp_mst_topology_mgr *mgr);

> > >  #endif

> > > -- 

> > > 2.7.4

> > > 

> > 

> 

> _______________________________________________

> Intel-gfx mailing list

> Intel-gfx@lists.freedesktop.org

> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox

Patch

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 681d5f9..b8e2cea 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -31,6 +31,7 @@ 
 #include <drm/drm_mode.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_print.h>
+#include <drm/drm_dp_mst_helper.h>
 #include <linux/sync_file.h>
 
 #include "drm_crtc_internal.h"
@@ -62,6 +63,7 @@  void drm_atomic_state_default_release(struct drm_atomic_state *state)
 	kfree(state->connectors);
 	kfree(state->crtcs);
 	kfree(state->planes);
+	kfree(state->dp_mst_topologies);
 }
 EXPORT_SYMBOL(drm_atomic_state_default_release);
 
@@ -189,6 +191,18 @@  void drm_atomic_state_default_clear(struct drm_atomic_state *state)
 		state->planes[i].ptr = NULL;
 		state->planes[i].state = NULL;
 	}
+
+	for (i = 0; i < state->num_mst_topologies; i++) {
+		struct drm_dp_mst_topology_mgr *mgr = state->dp_mst_topologies[i].ptr;
+
+		if (!mgr)
+			continue;
+
+		kfree(state->dp_mst_topologies[i].state);
+		state->dp_mst_topologies[i].ptr = NULL;
+		state->dp_mst_topologies[i].state = NULL;
+	}
+
 }
 EXPORT_SYMBOL(drm_atomic_state_default_clear);
 
@@ -981,6 +995,58 @@  static void drm_atomic_plane_print_state(struct drm_printer *p,
 		plane->funcs->atomic_print_state(p, state);
 }
 
+struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
+		struct drm_dp_mst_topology_mgr *mgr)
+{
+
+	int ret, i;
+	size_t new_size;
+	struct __drm_dp_mst_topology_state *new_arr;
+	struct drm_dp_mst_topology_state *new_mst_state;
+	int num_topologies;
+	struct drm_mode_config *config = &mgr->dev->mode_config;
+
+	WARN_ON(!state->acquire_ctx);
+
+	ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);
+	if (ret)
+		return ERR_PTR(ret);
+
+	for (i = 0; i < state->num_mst_topologies; i++) {
+		if (mgr == state->dp_mst_topologies[i].ptr &&
+		    state->dp_mst_topologies[i].state) {
+			return state->dp_mst_topologies[i].state;
+		}
+	}
+
+	num_topologies = state->num_mst_topologies + 1;
+	new_size = sizeof(*state->dp_mst_topologies) * num_topologies;
+	new_arr = krealloc(state->dp_mst_topologies, new_size, GFP_KERNEL);
+	if (!new_arr)
+		return ERR_PTR(-ENOMEM);
+
+	state->dp_mst_topologies = new_arr;
+	memset(&state->dp_mst_topologies[state->num_mst_topologies], 0,
+		sizeof(*state->dp_mst_topologies));
+
+	new_mst_state = kmalloc(sizeof(*mgr->state), GFP_KERNEL);
+	if (!new_mst_state)
+		return ERR_PTR(-ENOMEM);
+
+	new_mst_state->avail_slots = mgr->state->avail_slots;
+	state->dp_mst_topologies[state->num_mst_topologies].state = new_mst_state;
+	state->dp_mst_topologies[state->num_mst_topologies].ptr = mgr;
+	state->num_mst_topologies = num_topologies;
+	new_mst_state->mgr = mgr;
+	mgr->state->state = state;
+
+	DRM_DEBUG_ATOMIC("Added [MST Topology w/ base connector:%d] %p state to %p\n",
+			 mgr->conn_base_id, new_mst_state, state);
+
+	return new_mst_state;
+}
+EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
+
 /**
  * drm_atomic_get_connector_state - get connector state
  * @state: global atomic state object
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 5e52244..1cd38b7 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -30,6 +30,7 @@ 
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_dp_mst_helper.h>
 #include <linux/dma-fence.h>
 
 #include "drm_crtc_internal.h"
@@ -1992,6 +1993,15 @@  void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
 		connector->state->state = NULL;
 	}
 
+	for (i = 0; i < state->num_mst_topologies; i++) {
+		struct drm_dp_mst_topology_mgr *mgr;
+
+		mgr = state->dp_mst_topologies[i].ptr;
+		mgr->state->state = state;
+		swap(state->dp_mst_topologies[i].state, mgr->state);
+		mgr->state->state = NULL;
+	}
+
 	for_each_crtc_in_state(state, crtc, crtc_state, i) {
 		crtc->state->state = state;
 		swap(state->crtcs[i].state, crtc->state);
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index d42a6c0..1be19e1 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2042,6 +2042,9 @@  int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 			goto out_unlock;
 		}
 
+		/* max. time slots - one slot for MTP header */
+		mgr->state->avail_slots = 63;
+
 		/* add initial branch device at LCT 1 */
 		mstb = drm_dp_add_mst_branch_device(1, NULL);
 		if (mstb == NULL) {
@@ -2973,6 +2976,11 @@  int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
 	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
 	if (!mgr->proposed_vcpis)
 		return -ENOMEM;
+	mgr->state = kzalloc(sizeof(*mgr->state), GFP_KERNEL);
+	if (!mgr->state)
+		return -ENOMEM;
+	mgr->state->mgr = mgr;
+
 	set_bit(0, &mgr->payload_mask);
 	if (test_calc_pbn_mode() < 0)
 		DRM_ERROR("MST PBN self-test failed\n");
@@ -2995,6 +3003,8 @@  void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
 	kfree(mgr->proposed_vcpis);
 	mgr->proposed_vcpis = NULL;
 	mutex_unlock(&mgr->payload_lock);
+	kfree(mgr->state);
+	mgr->state = NULL;
 	mgr->dev = NULL;
 	mgr->aux = NULL;
 }
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index fd2d971..7ac5ed6 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -153,6 +153,11 @@  struct __drm_connnectors_state {
 	struct drm_connector_state *state;
 };
 
+struct __drm_dp_mst_topology_state {
+	struct drm_dp_mst_topology_mgr *ptr;
+	struct drm_dp_mst_topology_state *state;
+};
+
 /**
  * struct drm_atomic_state - the global state object for atomic updates
  * @ref: count of all references to this state (will not be freed until zero)
@@ -164,6 +169,8 @@  struct __drm_connnectors_state {
  * @crtcs: pointer to array of CRTC pointers
  * @num_connector: size of the @connectors and @connector_states arrays
  * @connectors: pointer to array of structures with per-connector data
+ * @num_mst_topologies: size of the @dp_mst_topologies array
+ * @dp_mst_topologies: pointer to array of structures with per-MST topology manager data
  * @acquire_ctx: acquire context for this atomic modeset state update
  */
 struct drm_atomic_state {
@@ -177,6 +184,8 @@  struct drm_atomic_state {
 	struct __drm_crtcs_state *crtcs;
 	int num_connector;
 	struct __drm_connnectors_state *connectors;
+	int num_mst_topologies;
+	struct __drm_dp_mst_topology_state *dp_mst_topologies;
 
 	struct drm_modeset_acquire_ctx *acquire_ctx;
 
@@ -250,6 +259,10 @@  int drm_atomic_connector_set_property(struct drm_connector *connector,
 		struct drm_connector_state *state, struct drm_property *property,
 		uint64_t val);
 
+struct drm_dp_mst_topology_state * __must_check
+drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
+				  struct drm_dp_mst_topology_mgr *mgr);
+
 /**
  * drm_atomic_get_existing_crtc_state - get crtc state, if it exists
  * @state: global atomic state object
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index 98d3c73..0a9bf20 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -403,6 +403,12 @@  struct drm_dp_payload {
 	int vcpi;
 };
 
+struct drm_dp_mst_topology_state {
+	int avail_slots;
+	struct drm_atomic_state *state;
+	struct drm_dp_mst_topology_mgr *mgr;
+};
+
 /**
  * struct drm_dp_mst_topology_mgr - DisplayPort MST manager
  *
@@ -481,6 +487,11 @@  struct drm_dp_mst_topology_mgr {
 	int pbn_div;
 
 	/**
+	 *  @state: MST topology manager state for atomic modesetting drivers
+	 */
+	struct drm_dp_mst_topology_state *state;
+
+	/**
 	 * @qlock: protects @tx_msg_downq, the tx_slots in struct
 	 * &drm_dp_mst_branch and txmsg->state once they are queued
 	 */
@@ -596,4 +607,6 @@  void drm_dp_mst_dump_topology(struct seq_file *m,
 
 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
+struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
+					struct drm_dp_mst_topology_mgr *mgr);
 #endif