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author | Brian Starkey <brian.starkey@arm.com> | 2017-03-29 17:42:33 +0100 |
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committer | Liviu Dudau <Liviu.Dudau@arm.com> | 2018-06-20 15:29:18 +0100 |
commit | b13cc8dd588434e2aec781e6d12224e4c408ac18 (patch) | |
tree | c202a3e17b01d1db38cebd680dd7d5cdc0f641cf /drivers/gpu/drm/drm_writeback.c | |
parent | 935774cd71fe604cc8ed24adcb507d7784255672 (diff) | |
download | linux-b13cc8dd588434e2aec781e6d12224e4c408ac18.tar.gz linux-b13cc8dd588434e2aec781e6d12224e4c408ac18.tar.bz2 linux-b13cc8dd588434e2aec781e6d12224e4c408ac18.zip |
drm: writeback: Add out-fences for writeback connectors
Add the WRITEBACK_OUT_FENCE_PTR property to writeback connectors, to
enable userspace to get a fence which will signal once the writeback is
complete. It is not allowed to request an out-fence without a
framebuffer attached to the connector.
A timeline is added to drm_writeback_connector for use by the writeback
out-fences.
In the case of a commit failure or DRM_MODE_ATOMIC_TEST_ONLY, the fence
is set to -1.
Changes from v2:
- Rebase onto Gustavo Padovan's v9 explicit sync series
- Change out_fence_ptr type to s32 __user *
- Set *out_fence_ptr to -1 in drm_atomic_connector_set_property
- Store fence in drm_writeback_job
Gustavo Padovan:
- Move out_fence_ptr out of connector_state
- Signal fence from drm_writeback_signal_completion instead of
in driver directly
Changes from v3:
- Rebase onto commit 7e9081c5aac7 ("drm/fence: fix memory overwrite
when setting out_fence fd") (change out_fence_ptr to s32 __user *,
for real this time.)
- Update documentation around WRITEBACK_OUT_FENCE_PTR
Signed-off-by: Brian Starkey <brian.starkey@arm.com>
[rebased and fixed conflicts]
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/229036/
Diffstat (limited to 'drivers/gpu/drm/drm_writeback.c')
-rw-r--r-- | drivers/gpu/drm/drm_writeback.c | 109 |
1 files changed, 107 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c index e5b8a4b79724..827395071f0b 100644 --- a/drivers/gpu/drm/drm_writeback.c +++ b/drivers/gpu/drm/drm_writeback.c @@ -14,6 +14,7 @@ #include <drm/drm_property.h> #include <drm/drm_writeback.h> #include <drm/drmP.h> +#include <linux/dma-fence.h> /** * DOC: overview @@ -31,6 +32,16 @@ * framebuffer applies only to a single commit (see below). A framebuffer may * not be attached while the CRTC is off. * + * 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 + * WRITEBACK_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 some additional properties, which userspace * can use to query and control them: * @@ -47,8 +58,54 @@ * data is an array of u32 DRM_FORMAT_* fourcc values. * Userspace can use this blob to find out what pixel formats are supported * by the connector's writeback engine. + * + * "WRITEBACK_OUT_FENCE_PTR": + * Userspace can use this property to provide a pointer for the kernel to + * fill with a sync_file file descriptor, which will signal once the + * writeback is finished. The value should be the address of a 32-bit + * signed integer, cast to a u64. + * 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_wb_connector(x) container_of(x->lock, \ + struct drm_writeback_connector, \ + fence_lock) + +static const char *drm_writeback_fence_get_driver_name(struct dma_fence *fence) +{ + struct drm_writeback_connector *wb_connector = + fence_to_wb_connector(fence); + + return wb_connector->base.dev->driver->name; +} + +static const char * +drm_writeback_fence_get_timeline_name(struct dma_fence *fence) +{ + struct drm_writeback_connector *wb_connector = + fence_to_wb_connector(fence); + + return wb_connector->timeline_name; +} + +static bool drm_writeback_fence_enable_signaling(struct dma_fence *fence) +{ + return true; +} + +static const struct dma_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 = dma_fence_default_wait, +}; + static int create_writeback_properties(struct drm_device *dev) { struct drm_property *prop; @@ -72,6 +129,15 @@ static int create_writeback_properties(struct drm_device *dev) dev->mode_config.writeback_pixel_formats_property = prop; } + if (!dev->mode_config.writeback_out_fence_ptr_property) { + prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC, + "WRITEBACK_OUT_FENCE_PTR", 0, + U64_MAX); + if (!prop) + return -ENOMEM; + dev->mode_config.writeback_out_fence_ptr_property = prop; + } + return 0; } @@ -141,6 +207,15 @@ int drm_writeback_connector_init(struct drm_device *dev, INIT_LIST_HEAD(&wb_connector->job_queue); spin_lock_init(&wb_connector->job_lock); + wb_connector->fence_context = dma_fence_context_alloc(1); + spin_lock_init(&wb_connector->fence_lock); + snprintf(wb_connector->timeline_name, + sizeof(wb_connector->timeline_name), + "CONNECTOR:%d-%s", connector->base.id, connector->name); + + drm_object_attach_property(&connector->base, + config->writeback_out_fence_ptr_property, 0); + drm_object_attach_property(&connector->base, config->writeback_fb_id_property, 0); @@ -210,6 +285,7 @@ static void cleanup_work(struct work_struct *work) /** * drm_writeback_signal_completion - Signal the completion of a writeback job * @wb_connector: The writeback connector whose job is complete + * @status: Status code to set in the writeback out_fence (0 for success) * * Drivers should call this to signal the completion of a previously queued * writeback job. It should be called as soon as possible after the hardware @@ -223,7 +299,8 @@ static void cleanup_work(struct work_struct *work) * See also: drm_writeback_queue_job() */ void -drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector) +drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector, + int status) { unsigned long flags; struct drm_writeback_job *job; @@ -232,8 +309,15 @@ drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector) job = list_first_entry_or_null(&wb_connector->job_queue, struct drm_writeback_job, list_entry); - if (job) + if (job) { list_del(&job->list_entry); + if (job->out_fence) { + if (status) + dma_fence_set_error(job->out_fence, status); + dma_fence_signal(job->out_fence); + dma_fence_put(job->out_fence); + } + } spin_unlock_irqrestore(&wb_connector->job_lock, flags); if (WARN_ON(!job)) @@ -243,3 +327,24 @@ drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector) queue_work(system_long_wq, &job->cleanup_work); } EXPORT_SYMBOL(drm_writeback_signal_completion); + +struct dma_fence * +drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector) +{ + struct dma_fence *fence; + + if (WARN_ON(wb_connector->base.connector_type != + DRM_MODE_CONNECTOR_WRITEBACK)) + return NULL; + + fence = kzalloc(sizeof(*fence), GFP_KERNEL); + if (!fence) + return NULL; + + dma_fence_init(fence, &drm_writeback_fence_ops, + &wb_connector->fence_lock, wb_connector->fence_context, + ++wb_connector->fence_seqno); + + return fence; +} +EXPORT_SYMBOL(drm_writeback_get_out_fence); |