Re: [PATCH v3 4/8] drm: Add driver-private objects to atomic state

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 02/16/2017 05:43 AM, Pandiyan, Dhinakaran wrote:
On Wed, 2017-02-15 at 16:53 +0530, Archit Taneja wrote:
Hi,

On 02/09/2017 12:08 PM, Dhinakaran Pandiyan wrote:
It is necessary to track states for objects other than connector, crtc
and plane for atomic modesets. But adding objects like DP MST link
bandwidth to drm_atomic_state would mean that a non-core object will be
modified by the core helper functions for swapping and clearing
it's state. So, lets add void * objects and helper functions that operate
on void * types to keep these objects and states private to the core.
Drivers can then implement specific functions to swap and clear states.
The other advantage having just void * for these objects in
drm_atomic_state is that objects of different types can be managed in the
same state array.

v2: Added docs and new iterator to filter private objects (Daniel)

Suggested-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
---
 drivers/gpu/drm/drm_atomic.c        | 68 +++++++++++++++++++++++++++
 drivers/gpu/drm/drm_atomic_helper.c |  5 ++
 include/drm/drm_atomic.h            | 91 +++++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index a567310..1a9ffe8 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -57,6 +57,7 @@ void drm_atomic_state_default_release(struct drm_atomic_state *state)
 	kfree(state->connectors);
 	kfree(state->crtcs);
 	kfree(state->planes);
+	kfree(state->private_objs);
 }
 EXPORT_SYMBOL(drm_atomic_state_default_release);

@@ -184,6 +185,20 @@ 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_private_objs; i++) {
+		void *private_obj = state->private_objs[i].obj;
+		void *obj_state = state->private_objs[i].obj_state;
+
+		if (!private_obj)
+			continue;
+
+		state->private_objs[i].funcs->destroy_state(obj_state);
+		state->private_objs[i].obj = NULL;
+		state->private_objs[i].obj_state = NULL;
+		state->private_objs[i].funcs = NULL;
+	}
+
 }
 EXPORT_SYMBOL(drm_atomic_state_default_clear);

@@ -974,6 +989,59 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,
 }

 /**
+ * drm_atomic_get_private_obj_state - get private object state
+ * @state: global atomic state
+ * @obj: private object to get the state for
+ * @funcs: pointer to the struct of function pointers that identify the object
+ * type
+ *
+ * This function returns the private object state for the given private object,
+ * allocating the state if needed. It does not grab any locks as the caller is
+ * expected to care of any required locking.
+ *
+ * RETURNS:
+ *
+ * Either the allocated state or the error code encoded into a pointer.
+ */
+void *
+drm_atomic_get_private_obj_state(struct drm_atomic_state *state, void *obj,
+			      const struct drm_private_state_funcs *funcs)
+{
+	int index, num_objs, i;
+	size_t size;
+	struct __drm_private_objs_state *arr;
+
+	for (i = 0; i < state->num_private_objs; i++)
+		if (obj == state->private_objs[i].obj &&
+		    state->private_objs[i].obj_state)
+			return state->private_objs[i].obj_state;

Comparing this func to drm_atomic_get_plane_state/drm_atomic_get_crtc_state, it
doesn't seem to call drm_modeset_lock if the obj_state doesn't already exist. I
don't understand the locking stuff toowell, I just noticed this difference when
comparing this approach with what is done in the msm kms driver (where we
have subclassed drm_atomic_state to msm_kms_state).

Thanks,
Archit



The caller is expected to take care of any required locking. The
driver-private objects are opaque from core's pov, so the core is not
aware of necessary locks for that object type.

I had a look at the rest of the series, and I couldn't easily understand
whether the caller code protects the MST related driver private state. Is
it expected to be protect via the drm_mode_config.connection_mutex lock?

Thanks,
Archit

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx




[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]
  Powered by Linux