Re: [PATCH v8 2/3] drm/fence: add fence timeline to drm_crtc

Sean Paul
2016-11-11T15:54:48Z

On Fri, Nov 11, 2016 at 12:16 AM, Gustavo Padovan <gustavo@padovan.org> 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
>
> v5: Comment by Daniel Vetter
> - Add doc for drm_crtc_fence_ops
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Reviewed-by: Sean Paul <seanpaul@chromium.org>

> ---
> drivers/gpu/drm/drm_crtc.c | 31 +++++++++++++++++++++++++++++++
> include/drm/drm_crtc.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 76 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 154e040..9b9881b 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 11780a9..0870de1 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>
> @@ -739,9 +741,52 @@ 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];
> };
>
> /**
> + * dma_crtc_fence_ops - fence ops for the drm_crtc timeline
> + *
> + * It contains the dma_fence_ops that should be called by the dma_fence
> + * code. CRTC core should use this ops when initializing fences.
> + */
> +extern const struct dma_fence_ops drm_crtc_fence_ops;
> +
> +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
> * @crtc: CRTC whose configuration we're about to change
> --
> 2.5.5
>