Re: [PATCH 01/18] drm/i915: Comments for semaphore clarification

Jani Nikula
2012-11-07T13:25:12Z

On Tue, 06 Nov 2012, Ben Widawsky <ben@bwidawsk.net> wrote:
> Semaphores are tied very closely to the rings in the GPU. Trivial patch
> adds comments to the existing code so that when we add new rings we can
> include comments there as well. It also helps distinguish the ring to
> semaphore mailbox interactions by using the ringname in the semaphore
> data structures.
>
> This patch should have no functional impact.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

>
> A subset of this patch was:
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 12 ++++++------
> drivers/gpu/drm/i915/intel_ringbuffer.c | 18 +++++++++---------
> drivers/gpu/drm/i915/intel_ringbuffer.h | 2 +-
> 3 files changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 9118bd1..f82755e 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -252,12 +252,12 @@
> #define MI_SEMAPHORE_UPDATE (1<<21)
> #define MI_SEMAPHORE_COMPARE (1<<20)
> #define MI_SEMAPHORE_REGISTER (1<<18)
> -#define MI_SEMAPHORE_SYNC_RV (2<<16)
> -#define MI_SEMAPHORE_SYNC_RB (0<<16)
> -#define MI_SEMAPHORE_SYNC_VR (0<<16)
> -#define MI_SEMAPHORE_SYNC_VB (2<<16)
> -#define MI_SEMAPHORE_SYNC_BR (2<<16)
> -#define MI_SEMAPHORE_SYNC_BV (0<<16)
> +#define MI_SEMAPHORE_SYNC_RB (0<<16) /* RCS wait for BCS (BRSYNC) */
> +#define MI_SEMAPHORE_SYNC_RV (2<<16) /* RCS wait for VCS (VRSYNC) */
> +#define MI_SEMAPHORE_SYNC_VR (0<<16) /* VCS wait for RCS (RVSYNC) */
> +#define MI_SEMAPHORE_SYNC_VB (2<<16) /* VCS wait for BCS (BVSYNC) */
> +#define MI_SEMAPHORE_SYNC_BV (0<<16) /* BCS wait for VCS (VBSYNC) */
> +#define MI_SEMAPHORE_SYNC_BR (2<<16) /* BCS wait for RCS (RBSYNC) */
> #define MI_SEMAPHORE_SYNC_INVALID (1<<0)
> /*
> * 3D instructions used by the kernel
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index a035ac2..423948f 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -1503,9 +1503,9 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
> ring->irq_enable_mask = GT_USER_INTERRUPT;
> ring->get_seqno = gen6_ring_get_seqno;
> ring->sync_to = gen6_ring_sync;
> - ring->semaphore_register[0] = MI_SEMAPHORE_SYNC_INVALID;
> - ring->semaphore_register[1] = MI_SEMAPHORE_SYNC_RV;
> - ring->semaphore_register[2] = MI_SEMAPHORE_SYNC_RB;
> + ring->semaphore_register[RCS] = MI_SEMAPHORE_SYNC_INVALID;
> + ring->semaphore_register[VCS] = MI_SEMAPHORE_SYNC_RV;
> + ring->semaphore_register[BCS] = MI_SEMAPHORE_SYNC_RB;
> ring->signal_mbox[0] = GEN6_VRSYNC;
> ring->signal_mbox[1] = GEN6_BRSYNC;
> } else if (IS_GEN5(dev)) {
> @@ -1639,9 +1639,9 @@ int intel_init_bsd_ring_buffer(struct drm_device *dev)
> ring->irq_put = gen6_ring_put_irq;
> ring->dispatch_execbuffer = gen6_ring_dispatch_execbuffer;
> ring->sync_to = gen6_ring_sync;
> - ring->semaphore_register[0] = MI_SEMAPHORE_SYNC_VR;
> - ring->semaphore_register[1] = MI_SEMAPHORE_SYNC_INVALID;
> - ring->semaphore_register[2] = MI_SEMAPHORE_SYNC_VB;
> + ring->semaphore_register[RCS] = MI_SEMAPHORE_SYNC_VR;
> + ring->semaphore_register[VCS] = MI_SEMAPHORE_SYNC_INVALID;
> + ring->semaphore_register[BCS] = MI_SEMAPHORE_SYNC_VB;
> ring->signal_mbox[0] = GEN6_RVSYNC;
> ring->signal_mbox[1] = GEN6_BVSYNC;
> } else {
> @@ -1684,9 +1684,9 @@ int intel_init_blt_ring_buffer(struct drm_device *dev)
> ring->irq_put = gen6_ring_put_irq;
> ring->dispatch_execbuffer = gen6_ring_dispatch_execbuffer;
> ring->sync_to = gen6_ring_sync;
> - ring->semaphore_register[0] = MI_SEMAPHORE_SYNC_BR;
> - ring->semaphore_register[1] = MI_SEMAPHORE_SYNC_BV;
> - ring->semaphore_register[2] = MI_SEMAPHORE_SYNC_INVALID;
> + ring->semaphore_register[RCS] = MI_SEMAPHORE_SYNC_BR;
> + ring->semaphore_register[VCS] = MI_SEMAPHORE_SYNC_BV;
> + ring->semaphore_register[BCS] = MI_SEMAPHORE_SYNC_INVALID;
> ring->signal_mbox[0] = GEN6_RBSYNC;
> ring->signal_mbox[1] = GEN6_VBSYNC;
> ring->init = init_ring_common;
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 5af65b8..df1a0a2 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -89,7 +89,7 @@ struct intel_ring_buffer {
> struct intel_ring_buffer *to,
> u32 seqno);
>
> - u32 semaphore_register[3]; /*our mbox written by others */
> + u32 semaphore_register[I915_NUM_RINGS]; /*our mbox written by others */
> u32 signal_mbox[2]; /* mboxes this ring signals to */
> /**
> * List of objects currently involved in rendering from the
> --
> 1.8.0
>
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