Re: [PATCH 07/13] drm/i915/bdw: implement semaphore wait

Ville Syrjälä
2014-01-30T12:48:13Z

On Wed, Jan 29, 2014 at 11:55:27AM -0800, Ben Widawsky wrote:
> Semaphore waits use a new instruction, MI_SEMAPHORE_WAIT. The seqno to
> wait on is all well defined by the table in the previous patch. There is
> nothing else different from previous GEN's semaphore synchronization
> code.
>
> v2: Update macros to not require the other ring's ring->id (Chris)
>
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 3 ++
> drivers/gpu/drm/i915/intel_ringbuffer.c | 66 +++++++++++++++------------------
> drivers/gpu/drm/i915/intel_ringbuffer.h | 30 +++++++++++++++
> 3 files changed, 62 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 8b745dc..6e8edaf 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -243,6 +243,9 @@
> #define MI_RESTORE_INHIBIT (1<<0)
> #define MI_SEMAPHORE_SIGNAL MI_INSTR(0x1b, 0) /* GEN8+ */
> #define MI_SEMAPHORE_TARGET(engine) ((engine)<<15)
> +#define MI_SEMAPHORE_WAIT MI_INSTR(0x1c, 2) /* GEN8+ */
> +#define MI_SEMAPHORE_POLL (1<<15)
> +#define MI_SEMAPHORE_SAD_GTE_SDD (1<<12)
> #define MI_STORE_DWORD_IMM MI_INSTR(0x20, 1)
> #define MI_MEM_VIRTUAL (1 << 22) /* 965+ only */
> #define MI_STORE_DWORD_INDEX MI_INSTR(0x21, 1)
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index b750835..3cfcc78 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -797,6 +797,31 @@ static inline bool i915_gem_has_seqno_wrapped(struct drm_device *dev,
> * @signaller - ring which has, or will signal
> * @seqno - seqno which the waiter will block on
> */
> +
> +static int
> +gen8_ring_sync(struct intel_ring_buffer *waiter,
> + struct intel_ring_buffer *signaller,
> + u32 seqno)
> +{
> + struct drm_i915_private *dev_priv = waiter->dev->dev_private;
> + int ret;
> +
> + ret = intel_ring_begin(waiter, 4);
> + if (ret)
> + return ret;
> +
> + intel_ring_emit(waiter, MI_SEMAPHORE_WAIT |
> + MI_SEMAPHORE_GLOBAL_GTT |
> + MI_SEMAPHORE_SAD_GTE_SDD);
> + intel_ring_emit(waiter, seqno);
> + intel_ring_emit(waiter,
> + lower_32_bits(GEN8_WAIT_OFFSET(waiter, signaller->id)));
> + intel_ring_emit(waiter,
> + upper_32_bits(GEN8_WAIT_OFFSET(waiter, signaller->id)));
> + intel_ring_advance(waiter);
> + return 0;
> +}
> +
> static int
> gen6_ring_sync(struct intel_ring_buffer *waiter,
> struct intel_ring_buffer *signaller,
> @@ -1939,39 +1964,6 @@ static int gen6_ring_flush(struct intel_ring_buffer *ring,
> return 0;
> }
>
> -/* seqno size is actually only a uint32, but since we plan to use MI_FLUSH_DW to
> - * do the writes, and that must have qw aligned offsets, simply pretend it's 8b.
> - */
> -#define SEQNO_SIZE sizeof(uint64_t)
> -#define GEN8_SIGNAL_OFFSET(to) \
> - (i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
> - (ring->id * I915_NUM_RINGS * SEQNO_SIZE) + \
> - (SEQNO_SIZE * (to)))
> -
> -#define GEN8_WAIT_OFFSET(from) \
> - (i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
> - ((from) * I915_NUM_RINGS * SEQNO_SIZE) + \
> - (SEQNO_SIZE * ring->id))
> -
> -#define GEN8_RING_SEMAPHORE_INIT do { \
> - if (!dev_priv->semaphore_obj) { \
> - break; \
> - } \
> - ring->semaphore.signal_ggtt[RCS] = GEN8_SIGNAL_OFFSET(RCS); \
> - ring->semaphore.signal_ggtt[VCS] = GEN8_SIGNAL_OFFSET(VCS); \
> - ring->semaphore.signal_ggtt[BCS] = GEN8_SIGNAL_OFFSET(BCS); \
> - ring->semaphore.signal_ggtt[VECS] = GEN8_SIGNAL_OFFSET(VECS); \
> - ring->semaphore.mbox[RCS] = GEN8_WAIT_OFFSET(RCS); \
> - ring->semaphore.mbox[VCS] = GEN8_WAIT_OFFSET(VCS); \
> - ring->semaphore.mbox[BCS] = GEN8_WAIT_OFFSET(BCS); \
> - ring->semaphore.mbox[VECS] = GEN8_WAIT_OFFSET(VECS); \
> - ring->semaphore.signal_ggtt[ring->id] = MI_SEMAPHORE_SYNC_INVALID; \
> - ring->semaphore.mbox[ring->id] = GEN6_NOSYNC; \
> - } while(0)
> -#undef seqno_size
> -
> -
> -

Maybe stick this stuff into the header to begin with to avoid churn.

> int intel_init_render_ring_buffer(struct drm_device *dev)
> {
> drm_i915_private_t *dev_priv = dev->dev_private;
> @@ -2007,7 +1999,7 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
> ring->irq_enable_mask = GT_RENDER_USER_INTERRUPT;
> ring->get_seqno = gen6_ring_get_seqno;
> ring->set_seqno = ring_set_seqno;
> - ring->semaphore.sync_to = gen6_ring_sync;
> + ring->semaphore.sync_to = gen8_ring_sync;
> if (i915_semaphore_is_enabled(dev)) {
> BUG_ON(!dev_priv->semaphore_obj);
> ring->semaphore.signal = gen8_rcs_signal;
> @@ -2192,7 +2184,7 @@ int intel_init_bsd_ring_buffer(struct drm_device *dev)
> ring->irq_put = gen8_ring_put_irq;
> ring->dispatch_execbuffer =
> gen8_ring_dispatch_execbuffer;
> - ring->semaphore.sync_to = gen6_ring_sync;
> + ring->semaphore.sync_to = gen8_ring_sync;
> if (i915_semaphore_is_enabled(dev)) {
> ring->semaphore.signal = gen8_xcs_signal;
> GEN8_RING_SEMAPHORE_INIT;
> @@ -2257,7 +2249,7 @@ int intel_init_blt_ring_buffer(struct drm_device *dev)
> ring->irq_get = gen8_ring_get_irq;
> ring->irq_put = gen8_ring_put_irq;
> ring->dispatch_execbuffer = gen8_ring_dispatch_execbuffer;
> - ring->semaphore.sync_to = gen6_ring_sync;
> + ring->semaphore.sync_to = gen8_ring_sync;
> if (i915_semaphore_is_enabled(dev)) {
> ring->semaphore.signal = gen8_xcs_signal;
> GEN8_RING_SEMAPHORE_INIT;
> @@ -2306,7 +2298,7 @@ int intel_init_vebox_ring_buffer(struct drm_device *dev)
> ring->irq_get = gen8_ring_get_irq;
> ring->irq_put = gen8_ring_put_irq;
> ring->dispatch_execbuffer = gen8_ring_dispatch_execbuffer;
> - ring->semaphore.sync_to = gen6_ring_sync;
> + ring->semaphore.sync_to = gen8_ring_sync;
> if (i915_semaphore_is_enabled(dev)) {
> ring->semaphore.signal = gen8_xcs_signal;
> GEN8_RING_SEMAPHORE_INIT;
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index f1e7a66..ed55370 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -33,6 +33,36 @@ struct intel_hw_status_page {
> #define I915_READ_IMR(ring) I915_READ(RING_IMR((ring)->mmio_base))
> #define I915_WRITE_IMR(ring, val) I915_WRITE(RING_IMR((ring)->mmio_base), val)
>
> +/* seqno size is actually only a uint32, but since we plan to use MI_FLUSH_DW to
> + * do the writes, and that must have qw aligned offsets, simply pretend it's 8b.
> + */
> +#define i915_semaphore_seqno_size sizeof(uint64_t)
> +#define GEN8_SIGNAL_OFFSET(to) \
> + (i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
> + (ring->id * I915_NUM_RINGS * i915_semaphore_seqno_size) + \
> + (i915_semaphore_seqno_size * (to)))
> +
> +#define GEN8_WAIT_OFFSET(__ring, from) \
> + (i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
> + ((from) * I915_NUM_RINGS * i915_semaphore_seqno_size) + \
> + (i915_semaphore_seqno_size * (__ring)->id))
> +
> +#define GEN8_RING_SEMAPHORE_INIT do { \
> + if (!dev_priv->semaphore_obj) { \
> + break; \
> + } \
> + ring->semaphore.signal_ggtt[RCS] = GEN8_SIGNAL_OFFSET(RCS); \
> + ring->semaphore.signal_ggtt[VCS] = GEN8_SIGNAL_OFFSET(VCS); \
> + ring->semaphore.signal_ggtt[BCS] = GEN8_SIGNAL_OFFSET(BCS); \
> + ring->semaphore.signal_ggtt[VECS] = GEN8_SIGNAL_OFFSET(VECS); \
> + ring->semaphore.mbox[RCS] = GEN8_WAIT_OFFSET(ring, RCS); \
> + ring->semaphore.mbox[VCS] = GEN8_WAIT_OFFSET(ring, VCS); \
> + ring->semaphore.mbox[BCS] = GEN8_WAIT_OFFSET(ring, BCS); \
> + ring->semaphore.mbox[VECS] = GEN8_WAIT_OFFSET(ring, VECS); \
> + ring->semaphore.signal_ggtt[ring->id] = MI_SEMAPHORE_SYNC_INVALID; \
> + ring->semaphore.mbox[ring->id] = GEN6_NOSYNC; \
> + } while(0)
> +
> enum intel_ring_hangcheck_action {
> HANGCHECK_IDLE = 0,
> HANGCHECK_WAIT,
> --
> 1.8.5.3
>
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--
Ville Syrjälä
Intel OTC