Re: [PATCH v6 5/6] drm/fence: add fence timeline to drm_crtc

[Brian Starkey <brian.starkey@arm.com>]

On Fri, Oct 28, 2016 at 09:42:12AM +0200, Daniel Vetter wrote:
>On Thu, Oct 27, 2016 at 05:37:10PM -0200, Gustavo Padovan wrote:
>> From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>>
>> Create one timeline context for each CRTC to be able to handle out-fences
>> and signal them. It adds a few members to struct drm_crtc: fence_context,
>> where we store the context we get from fence_context_alloc(), the
>> fence seqno and the fence lock, that we pass in fence_init() to be
>> used by the fence.
>>
>> v2: Comment by Daniel Stone:
>> 	- add BUG_ON() to fence_to_crtc() macro
>>
>> v3: Comment by Ville Syrjälä
>> 	- Use more meaningful name as crtc timeline name
>>
>> v4: Comments by Brian Starkey
>> 	- Use even more meaninful name for the crtc timeline
>> 	- add doc for timeline_name
>>     Comment by Daniel Vetter
>> 	- use in-line style for comments
>>
>>     - rebase after fence -> dma_fence rename
>>
>> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>> ---
>>  drivers/gpu/drm/drm_crtc.c | 31 +++++++++++++++++++++++++++++++
>>  include/drm/drm_crtc.h     | 39 +++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 70 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
>> index 7878bfd..e2a06c8 100644
>> --- a/drivers/gpu/drm/drm_crtc.c
>> +++ b/drivers/gpu/drm/drm_crtc.c
>> @@ -165,6 +165,32 @@ static void drm_crtc_crc_fini(struct drm_crtc *crtc)
>>  #endif
>>  }
>>
>> +static const char *drm_crtc_fence_get_driver_name(struct dma_fence *fence)
>> +{
>> +	struct drm_crtc *crtc = fence_to_crtc(fence);
>> +
>> +	return crtc->dev->driver->name;
>> +}
>> +
>> +static const char *drm_crtc_fence_get_timeline_name(struct dma_fence *fence)
>> +{
>> +	struct drm_crtc *crtc = fence_to_crtc(fence);
>> +
>> +	return crtc->timeline_name;
>> +}
>> +
>> +static bool drm_crtc_fence_enable_signaling(struct dma_fence *fence)
>> +{
>> +	return true;
>> +}
>> +
>> +const struct dma_fence_ops drm_crtc_fence_ops = {
>> +	.get_driver_name = drm_crtc_fence_get_driver_name,
>> +	.get_timeline_name = drm_crtc_fence_get_timeline_name,
>> +	.enable_signaling = drm_crtc_fence_enable_signaling,
>> +	.wait = dma_fence_default_wait,
>> +};
>> +
>>  /**
>>   * drm_crtc_init_with_planes - Initialise a new CRTC object with
>>   *    specified primary and cursor planes.
>> @@ -222,6 +248,11 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
>>  		return -ENOMEM;
>>  	}
>>
>> +	crtc->fence_context = dma_fence_context_alloc(1);
>> +	spin_lock_init(&crtc->fence_lock);
>> +	snprintf(crtc->timeline_name, sizeof(crtc->timeline_name),
>> +		 "CRTC:%d-%s", crtc->base.id, crtc->name);
>> +
>>  	crtc->base.properties = &crtc->properties;
>>
>>  	list_add_tail(&crtc->head, &config->crtc_list);
>> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
>> index 719b6a8..278dbdd 100644
>> --- a/include/drm/drm_crtc.h
>> +++ b/include/drm/drm_crtc.h
>> @@ -32,6 +32,8 @@
>>  #include <linux/fb.h>
>>  #include <linux/hdmi.h>
>>  #include <linux/media-bus-format.h>
>> +#include <linux/srcu.h>
>> +#include <linux/dma-fence.h>
>>  #include <uapi/drm/drm_mode.h>
>>  #include <uapi/drm/drm_fourcc.h>
>>  #include <drm/drm_modeset_lock.h>
>> @@ -726,8 +728,45 @@ struct drm_crtc {
>>  	 */
>>  	struct drm_crtc_crc crc;
>>  #endif
>> +
>> +	/**
>> +	 * @fence_context:
>> +	 *
>> +	 * timeline context used for fence operations.
>> +	 */
>> +	unsigned int fence_context;
>> +
>> +	/**
>> +	 * @fence_lock:
>> +	 *
>> +	 * spinlock to protect the fences in the fence_context.
>> +	 */
>> +
>> +	spinlock_t fence_lock;
>> +	/**
>> +	 * @fence_seqno:
>> +	 *
>> +	 * Seqno variable used as monotonic counter for the fences
>> +	 * created on the CRTC's timeline.
>> +	 */
>> +	unsigned long fence_seqno;
>> +
>> +	/**
>> +	 * @timeline_name:
>> +	 *
>> +	 * The name of the CRTC's fence timeline.
>> +	 */
>> +	char timeline_name[32];
>>  };
>>
>> +extern const struct dma_fence_ops drm_crtc_fence_ops;
>> +
>
>Kerneldoc please. With that addressed:
>
>Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>

For my connector fences I exported a function to get the fence, then
you can keep the ops and fence_to_crtc private to drm_crtc.c. In that
case I think you can drop the BUG_ON.

Either way, lgtm.

Reviewed-by: Brian Starkey <brian.starkey@arm.com>

>> +static inline struct drm_crtc *fence_to_crtc(struct dma_fence *fence)
>> +{
>> +	BUG_ON(fence->ops != &drm_crtc_fence_ops);
>> +	return container_of(fence->lock, struct drm_crtc, fence_lock);
>> +}
>> +
>>  /**
>>   * struct drm_mode_set - new values for a CRTC config change
>>   * @fb: framebuffer to use for new config
>> --
>> 2.5.5
>>
>
>-- 
>Daniel Vetter
>Software Engineer, Intel Corporation
>http://blog.ffwll.ch
>
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