Hi Gustavo,
On Wed, Oct 26, 2016 at 07:40:29PM -0200, Gustavo Padovan wrote:
>2016-10-26 Brian Starkey <brian.starkey at arm.com>:
>
>> Add the OUT_FENCE_PTR property to writeback connectors, to enable
>> userspace to get a fence which will signal once the writeback is
>> complete.
>>
>> A timeline is added to drm_connector for use by the writeback
>> out-fences. It is up to drivers to check for a fence in the
>> connector_state and signal the it appropriately when their writeback has
>> finished.
>>
>> It is not allowed to request an out-fence without a framebuffer attached
>> to the connector.
>>
>> Signed-off-by: Brian Starkey <brian.starkey at arm.com>
>> ---
>> drivers/gpu/drm/drm_atomic.c | 60 +++++++++++++++++++++++---
>> drivers/gpu/drm/drm_atomic_helper.c | 5 ++-
>> drivers/gpu/drm/drm_writeback.c | 80
>> +++++++++++++++++++++++++++++++++++
>> include/drm/drm_connector.h | 14 ++++++
>> include/drm/drm_writeback.h | 2 +
>> 5 files changed, 155 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>> index 3f8fc97..061ea13 100644
>> --- a/drivers/gpu/drm/drm_atomic.c
>> +++ b/drivers/gpu/drm/drm_atomic.c
>> @@ -30,6 +30,7 @@
>> #include <drm/drm_atomic.h>
>> #include <drm/drm_mode.h>
>> #include <drm/drm_plane_helper.h>
>> +#include <drm/drm_writeback.h>
>> #include <linux/sync_file.h>
>>
>> #include "drm_crtc_internal.h"
>> @@ -646,6 +647,12 @@ static int drm_atomic_connector_check(struct
>> drm_connector *connector,
>> return -EINVAL;
>> }
>>
>> + if (state->out_fence && !state->fb) {
>> + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] requesting out-fence
>> without framebuffer\n",
>> + connector->base.id, connector->name);
>> + return -EINVAL;
>> + }
>> +
>> return 0;
>> }
>>
>> @@ -1047,6 +1054,8 @@ int drm_atomic_connector_set_property(struct
>> drm_connector *connector,
>> drm_atomic_set_fb_for_connector(state, fb);
>> if (fb)
>> drm_framebuffer_unreference(fb);
>> + } else if (property == config->prop_out_fence_ptr) {
>> + state->out_fence_ptr = u64_to_user_ptr(val);
>
>We need to move this out of the conn_state. For my v6 on CRTC out fences
>I added drm_atomic_set_out_fence_for_crtc() and
>drm_atomic_get_out_fence_for_crtc(). See padovan/fences.
>
Yep, will do. I was expecting this to change
>> } else if (connector->funcs->atomic_set_property) {
>> return connector->funcs->atomic_set_property(connector,
>> state, property, val);
>> @@ -1088,6 +1097,8 @@ drm_atomic_connector_get_property(struct drm_connector
>> *connector,
>> } else if (property == config->writeback_fb_id_property) {
>> /* Writeback framebuffer is one-shot, write and forget */
>> *val = 0;
>> + } else if (property == config->prop_out_fence_ptr) {
>> + *val = 0;
>> } else if (connector->funcs->atomic_get_property) {
>> return connector->funcs->atomic_get_property(connector,
>> state, property, val);
>> @@ -1736,6 +1747,39 @@ static int setup_out_fence(struct drm_out_fence_state
>> *fence_state,
>> return 0;
>> }
>>
>> +static int setup_connector_out_fences(struct drm_atomic_state *state,
>> + struct drm_out_fence_state *fence_state,
>> + int *fence_idx)
>> +{
>> + struct drm_connector *conn;
>> + struct drm_connector_state *conn_state;
>> + int i, ret;
>> +
>> + for_each_connector_in_state(state, conn, conn_state, i) {
>> + struct fence *fence;
>> +
>> + if (!conn_state->out_fence_ptr)
>> + continue;
>> +
>> + fence = drm_writeback_get_out_fence(conn, conn_state);
>> + if (!fence)
>> + return -ENOMEM;
>> +
>> + ret = setup_out_fence(&fence_state[(*fence_idx)++],
>> + conn_state->out_fence_ptr,
>> + fence);
>> + if (ret) {
>> + fence_put(fence);
>> + return ret;
>> + }
>> +
>> + /* One-time usage only */
>> + conn_state->out_fence_ptr = NULL;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> int drm_mode_atomic_ioctl(struct drm_device *dev,
>> void *data, struct drm_file *file_priv)
>> {
>> @@ -1868,8 +1912,8 @@ retry:
>> drm_mode_object_unreference(obj);
>> }
>>
>> - fence_state = kcalloc(dev->mode_config.num_crtc, sizeof(*fence_state),
>> - GFP_KERNEL);
>> + fence_state = kcalloc(dev->mode_config.num_crtc + state->num_connector,
>> + sizeof(*fence_state), GFP_KERNEL);
>> if (!fence_state) {
>> ret = -ENOMEM;
>> goto out;
>> @@ -1929,10 +1973,16 @@ retry:
>> * Below we call drm_atomic_state_free for it.
>> */
>> ret = drm_atomic_check_only(state);
>> - } else if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK) {
>> - ret = drm_atomic_nonblocking_commit(state);
>> } else {
>> - ret = drm_atomic_commit(state);
>> + ret = setup_connector_out_fences(state, fence_state,
>> + &fence_idx);
>> + if (ret)
>> + goto out;
>
>I'd do this before this block. At the DRM_MODE_ATOMIC_TEST_ONLY or we
>check or we commit. Moreover you should check if out_fences
>are not set with TEST_ONLY.
>
I don't quite follow the second sentence; you mean you'd rather I
was finished setting things up before the TEST_ONLY check? That sounds
OK.
For TEST_ONLY I actually think we shouldn't reject commits with
OUT_FENCE_PTRs and TEST_ONLY. I thought the idea of TEST_ONLY was for
userspace to build a commit, then see if it can work, then commit it
for real.
By rejecting TEST_ONLY + OUT_FENCE_PTRs you're saying userspace can
never test what it actually intends to commit. It has to test, then
add the out-fences, then commit and hope for the best.
How about always setting the out-fences to -1 for TEST_ONLY?
Thanks for the review,
-Brian
>> +
>> + if (arg->flags & DRM_MODE_ATOMIC_NONBLOCK)
>> + ret = drm_atomic_nonblocking_commit(state);
>> + else
>> + ret = drm_atomic_commit(state);
>> }
>>
>> if (!ret)
>> diff --git a/drivers/gpu/drm/drm_atomic_helper.c
>> b/drivers/gpu/drm/drm_atomic_helper.c
>> index bba8672..88da299 100644
>> --- a/drivers/gpu/drm/drm_atomic_helper.c
>> +++ b/drivers/gpu/drm/drm_atomic_helper.c
>> @@ -3234,8 +3234,9 @@ __drm_atomic_helper_connector_duplicate_state(struct
>> drm_connector *connector,
>> if (state->crtc)
>> drm_connector_reference(connector);
>>
>> - /* Don't copy over framebuffers, they are used only once */
>> + /* Don't copy over framebuffers or fences, they are used only once */
>> state->fb = NULL;
>> + state->out_fence = NULL;
>> }
>> EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
>>
>> @@ -3365,6 +3366,8 @@ __drm_atomic_helper_connector_destroy_state(struct
>> drm_connector_state *state)
>> drm_connector_unreference(state->connector);
>> if (state->fb)
>> drm_framebuffer_unreference(state->fb);
>> +
>> + fence_put(state->out_fence);
>> }
>> EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state);
>>
>> diff --git a/drivers/gpu/drm/drm_writeback.c
>> b/drivers/gpu/drm/drm_writeback.c
>> index 5a6e0ad..4a6ef30 100644
>> --- a/drivers/gpu/drm/drm_writeback.c
>> +++ b/drivers/gpu/drm/drm_writeback.c
>> @@ -11,6 +11,7 @@
>> #include <drm/drm_crtc.h>
>> #include <drm/drm_property.h>
>> #include <drm/drmP.h>
>> +#include <linux/fence.h>
>>
>> /**
>> * DOC: overview
>> @@ -32,6 +33,16 @@
>> * explicitly cleared in order to make a subsequent commit which doesn't use
>> * writeback.
>> *
>> + * Unlike with planes, when a writeback framebuffer is removed by userspace
>> DRM
>> + * makes no attempt to remove it from active use by the connector. This is
>> + * because no method is provided to abort a writeback operation, and in any
>> + * case making a new commit whilst a writeback is ongoing is undefined (see
>> + * OUT_FENCE_PTR below). As soon as the current writeback is finished, the
>> + * framebuffer will automatically no longer be in active use. As it will
>> also
>> + * have already been removed from the framebuffer list, there will be no
>> way for
>> + * any userspace application to retrieve a reference to it in the
>> intervening
>> + * period.
>> + *
>> * Writeback connectors have several additional properties, which userspace
>> * can use to query and control them:
>> *
>> @@ -52,8 +63,48 @@
>> * "PIXEL_FORMATS_SIZE":
>> * Immutable unsigned range property storing the number of entries in the
>> * PIXEL_FORMATS array.
>> + *
>> + * "OUT_FENCE_PTR":
>> + * Userspace can provide the address of a 64-bit integer in this property,
>> + * which will be filled with a sync_file file descriptor by the kernel.
>> + * The sync_file will signal when the associated writeback has finished.
>> + * Userspace should wait for this fence to signal before making another
>> + * commit affecting any of the same CRTCs, Planes or Connectors.
>> + * **Failure to do so will result in undefined behaviour.**
>> + * For this reason it is strongly recommended that all userspace
>> + * applications making use of writeback connectors *always* retrieve an
>> + * out-fence for the commit and use it appropriately.
>> + * From userspace, this property will always read as zero.
>> */
>>
>> +#define fence_to_connector(x) container_of(x->lock, struct drm_connector,
>> fence_lock)
>> +
>> +static const char *drm_writeback_fence_get_driver_name(struct fence *fence)
>> +{
>> + struct drm_connector *connector = fence_to_connector(fence);
>> +
>> + return connector->dev->driver->name;
>> +}
>> +
>> +static const char *drm_writeback_fence_get_timeline_name(struct fence
>> *fence)
>> +{
>> + struct drm_connector *connector = fence_to_connector(fence);
>> +
>> + return connector->timeline_name;
>> +}
>> +
>> +static bool drm_writeback_fence_enable_signaling(struct fence *fence)
>> +{
>> + return true;
>> +}
>> +
>> +static const struct fence_ops drm_writeback_fence_ops = {
>> + .get_driver_name = drm_writeback_fence_get_driver_name,
>> + .get_timeline_name = drm_writeback_fence_get_timeline_name,
>> + .enable_signaling = drm_writeback_fence_enable_signaling,
>> + .wait = fence_default_wait,
>> +};
>> +
>> /**
>> * create_writeback_properties - Create writeback connector-specific
>> properties
>> * @dev: DRM device
>> @@ -136,6 +187,14 @@ int drm_writeback_connector_init(struct drm_device *dev,
>> if (ret)
>> goto fail;
>>
>> + connector->fence_context = fence_context_alloc(1);
>> + spin_lock_init(&connector->fence_lock);
>> + snprintf(connector->timeline_name, sizeof(connector->timeline_name),
>> + "CONNECTOR:%d", connector->base.id);
>> +
>> + drm_object_attach_property(&connector->base,
>> + config->prop_out_fence_ptr, 0);
>> +
>> drm_object_attach_property(&connector->base,
>> config->writeback_fb_id_property, 0);
>>
>> @@ -155,3 +214,24 @@ fail:
>> return ret;
>> }
>> EXPORT_SYMBOL(drm_writeback_connector_init);
>> +
>> +struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
>> + struct drm_connector_state
>> *conn_state)
>> +{
>> + struct fence *fence;
>> +
>> + if (WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK))
>> + return NULL;
>> +
>> + fence = kzalloc(sizeof(*fence), GFP_KERNEL);
>> + if (!fence)
>> + return NULL;
>> +
>> + fence_init(fence, &drm_writeback_fence_ops, &connector->fence_lock,
>> + connector->fence_context, ++connector->fence_seqno);
>> +
>> + conn_state->out_fence = fence_get(fence);
>> +
>> + return fence;
>> +}
>> +EXPORT_SYMBOL(drm_writeback_get_out_fence);
>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>> index a5e3778..7d40537 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -199,6 +199,7 @@ int drm_display_info_set_bus_formats(struct
>> drm_display_info *info,
>> * @best_encoder: can be used by helpers and drivers to select the encoder
>> * @state: backpointer to global drm_atomic_state
>> * @fb: Writeback framebuffer, for DRM_MODE_CONNECTOR_WRITEBACK
>> + * @out_fence: Fence which will clear when the framebuffer write has
>> finished
>> */
>> struct drm_connector_state {
>> struct drm_connector *connector;
>> @@ -216,6 +217,9 @@ struct drm_connector_state {
>> struct drm_atomic_state *state;
>>
>> struct drm_framebuffer *fb; /* do not write directly, use
>> drm_atomic_set_fb_for_connector() */
>> +
>> + struct fence *out_fence;
>> + u64 __user *out_fence_ptr;
>> };
>>
>> /**
>> @@ -546,6 +550,10 @@ struct drm_cmdline_mode {
>> * @tile_v_loc: vertical location of this tile
>> * @tile_h_size: horizontal size of this tile.
>> * @tile_v_size: vertical size of this tile.
>> + * @fence_context: context for fence signalling
>> + * @fence_lock: fence lock for the fence context
>> + * @fence_seqno: seqno variable to create fences
>> + * @timeline_name: fence timeline name
>> *
>> * Each connector may be connected to one or more CRTCs, or may be clonable
>> by
>> * another connector if they can share a CRTC. Each connector also has a
>> specific
>> @@ -694,6 +702,12 @@ struct drm_connector {
>> uint8_t num_h_tile, num_v_tile;
>> uint8_t tile_h_loc, tile_v_loc;
>> uint16_t tile_h_size, tile_v_size;
>> +
>> + /* fence timelines info for DRM out-fences */
>> + unsigned int fence_context;
>> + spinlock_t fence_lock;
>> + unsigned long fence_seqno;
>> + char timeline_name[32];
>> };
>>
>> #define obj_to_connector(x) container_of(x, struct drm_connector, base)
>> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
>> index afdc2742..01f33bc 100644
>> --- a/include/drm/drm_writeback.h
>> +++ b/include/drm/drm_writeback.h
>> @@ -16,4 +16,6 @@ int drm_writeback_connector_init(struct drm_device *dev,
>> const struct drm_connector_funcs *funcs,
>> u32 *formats, int n_formats);
>>
>> +struct fence *drm_writeback_get_out_fence(struct drm_connector *connector,
>> + struct drm_connector_state
>> *conn_state);
>> #endif
>> --
>> 1.7.9.5
>>
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>> dri-devel at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
