Chris Wilson <ch...@chris-wilson.co.uk> writes:

> Emulate HW to track and manage ELSP queue. A set of SW ports are defined
> and requests are assigned to these ports before submitting them to HW. This
> helps in cleaning up incomplete requests during reset recovery easier
> especially after engine reset by decoupling elsp queue management. This
> will become more clear in the next patch.
>
> In the engine reset case we want to resume where we left-off after skipping
> the incomplete batch which requires checking the elsp queue, removing
> element and fixing elsp_submitted counts in some cases. Instead of directly
> manipulating the elsp queue from reset path we can examine these ports, fix
> up ringbuffer pointers using the incomplete request and restart submissions
> again after reset.
>
> Cc: Tvrtko Ursulin <tvrtko.ursu...@intel.com>
> Cc: Mika Kuoppala <mika.kuopp...@intel.com>
> Cc: Arun Siluvery <arun.siluv...@linux.intel.com>
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
> Link: 
> http://patchwork.freedesktop.org/patch/msgid/1470414607-32453-3-git-send-email-arun.siluv...@linux.intel.com
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c     |   2 +-
>  drivers/gpu/drm/i915/i915_gem.c         |  13 +-
>  drivers/gpu/drm/i915/i915_gem_request.c |   1 -
>  drivers/gpu/drm/i915/i915_gem_request.h |  21 +-
>  drivers/gpu/drm/i915/intel_lrc.c        | 405 
> ++++++++++++++------------------
>  drivers/gpu/drm/i915/intel_lrc.h        |   2 -
>  drivers/gpu/drm/i915/intel_ringbuffer.h |   7 +-
>  7 files changed, 188 insertions(+), 263 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c 
> b/drivers/gpu/drm/i915/i915_debugfs.c
> index d89359a50742..5f932ebc6ff1 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -2074,7 +2074,7 @@ static int i915_execlists(struct seq_file *m, void 
> *data)
>               status_pointer = I915_READ(RING_CONTEXT_STATUS_PTR(engine));
>               seq_printf(m, "\tStatus pointer: 0x%08X\n", status_pointer);
>  
> -             read_pointer = engine->next_context_status_buffer;
> +             read_pointer = GEN8_CSB_READ_PTR(status_pointer);
>               write_pointer = GEN8_CSB_WRITE_PTR(status_pointer);
>               if (read_pointer > write_pointer)
>                       write_pointer += GEN8_CSB_ENTRIES;
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index d37b44126942..838a275e7fac 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2575,6 +2575,9 @@ static void i915_gem_reset_engine_cleanup(struct 
> intel_engine_cs *engine)
>       struct drm_i915_gem_request *request;
>       struct intel_ring *ring;
>  
> +     /* Ensure irq handler finishes, and not run again. */
> +     tasklet_kill(&engine->irq_tasklet);
> +
>       /* Mark all pending requests as complete so that any concurrent
>        * (lockless) lookup doesn't try and wait upon the request as we
>        * reset it.
> @@ -2588,10 +2591,12 @@ static void i915_gem_reset_engine_cleanup(struct 
> intel_engine_cs *engine)
>        */
>  
>       if (i915.enable_execlists) {
> -             /* Ensure irq handler finishes or is cancelled. */
> -             tasklet_kill(&engine->irq_tasklet);
> -
> -             intel_execlists_cancel_requests(engine);
> +             spin_lock(&engine->execlist_lock);
> +             INIT_LIST_HEAD(&engine->execlist_queue);
> +             i915_gem_request_put(engine->execlist_port[0].request);
> +             i915_gem_request_put(engine->execlist_port[1].request);
> +             memset(engine->execlist_port, 0, sizeof(engine->execlist_port));
> +             spin_unlock(&engine->execlist_lock);
>       }
>  
>       /*
> diff --git a/drivers/gpu/drm/i915/i915_gem_request.c 
> b/drivers/gpu/drm/i915/i915_gem_request.c
> index 9cc08a1e43c6..ec613fd5e01c 100644
> --- a/drivers/gpu/drm/i915/i915_gem_request.c
> +++ b/drivers/gpu/drm/i915/i915_gem_request.c
> @@ -402,7 +402,6 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
>       req->previous_context = NULL;
>       req->file_priv = NULL;
>       req->batch = NULL;
> -     req->elsp_submitted = 0;
>  
>       /*
>        * Reserve space in the ring buffer for all the commands required to
> diff --git a/drivers/gpu/drm/i915/i915_gem_request.h 
> b/drivers/gpu/drm/i915/i915_gem_request.h
> index 2faa3bb4c39b..a231bd318ef0 100644
> --- a/drivers/gpu/drm/i915/i915_gem_request.h
> +++ b/drivers/gpu/drm/i915/i915_gem_request.h
> @@ -137,27 +137,8 @@ struct drm_i915_gem_request {
>       /** file_priv list entry for this request */
>       struct list_head client_list;
>  
> -     /**
> -      * The ELSP only accepts two elements at a time, so we queue
> -      * context/tail pairs on a given queue (ring->execlist_queue) until the
> -      * hardware is available. The queue serves a double purpose: we also use
> -      * it to keep track of the up to 2 contexts currently in the hardware
> -      * (usually one in execution and the other queued up by the GPU): We
> -      * only remove elements from the head of the queue when the hardware
> -      * informs us that an element has been completed.
> -      *
> -      * All accesses to the queue are mediated by a spinlock
> -      * (ring->execlist_lock).
> -      */
> -
> -     /** Execlist link in the submission queue.*/
> +     /** Link in the execlist submission queue, guarded by execlist_lock. */
>       struct list_head execlist_link;
> -
> -     /** Execlists no. of times this request has been sent to the ELSP */
> -     int elsp_submitted;
> -
> -     /** Execlists context hardware id. */
> -     unsigned int ctx_hw_id;
>  };
>  
>  extern const struct fence_ops i915_fence_ops;
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c 
> b/drivers/gpu/drm/i915/intel_lrc.c
> index e9cb4a906009..864b5248279a 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -156,6 +156,11 @@
>  #define GEN8_CTX_STATUS_COMPLETE     (1 << 4)
>  #define GEN8_CTX_STATUS_LITE_RESTORE (1 << 15)
>  
> +#define GEN8_CTX_STATUS_COMPLETED_MASK \
> +      (GEN8_CTX_STATUS_ACTIVE_IDLE | \
> +       GEN8_CTX_STATUS_PREEMPTED | \
> +       GEN8_CTX_STATUS_ELEMENT_SWITCH)
> +
>  #define CTX_LRI_HEADER_0             0x01
>  #define CTX_CONTEXT_CONTROL          0x02
>  #define CTX_RING_HEAD                        0x04
> @@ -263,12 +268,10 @@ logical_ring_init_platform_invariants(struct 
> intel_engine_cs *engine)
>  {
>       struct drm_i915_private *dev_priv = engine->i915;
>  
> -     if (IS_GEN8(dev_priv) || IS_GEN9(dev_priv))
> -             engine->idle_lite_restore_wa = ~0;
> -
> -     engine->disable_lite_restore_wa = (IS_SKL_REVID(dev_priv, 0, 
> SKL_REVID_B0) ||
> -                                     IS_BXT_REVID(dev_priv, 0, 
> BXT_REVID_A1)) &&
> -                                     (engine->id == VCS || engine->id == 
> VCS2);
> +     engine->disable_lite_restore_wa =
> +             (IS_SKL_REVID(dev_priv, 0, SKL_REVID_B0) ||
> +              IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1)) &&
> +             (engine->id == VCS || engine->id == VCS2);
>  
>       engine->ctx_desc_template = GEN8_CTX_VALID;
>       if (IS_GEN8(dev_priv))
> @@ -351,11 +354,11 @@ execlists_update_context_pdps(struct i915_hw_ppgtt 
> *ppgtt, u32 *reg_state)
>       ASSIGN_CTX_PDP(ppgtt, reg_state, 0);
>  }
>  
> -static void execlists_update_context(struct drm_i915_gem_request *rq)
> +static u64 execlists_update_context(struct drm_i915_gem_request *rq)
>  {
> -     struct intel_engine_cs *engine = rq->engine;
> +     struct intel_context *ce = &rq->ctx->engine[rq->engine->id];
>       struct i915_hw_ppgtt *ppgtt = rq->ctx->ppgtt;
> -     uint32_t *reg_state = rq->ctx->engine[engine->id].lrc_reg_state;
> +     u32 *reg_state = ce->lrc_reg_state;
>  
>       reg_state[CTX_RING_TAIL+1] = intel_ring_offset(rq->ring, rq->tail);
>  
> @@ -366,26 +369,34 @@ static void execlists_update_context(struct 
> drm_i915_gem_request *rq)
>        */
>       if (ppgtt && !USES_FULL_48BIT_PPGTT(ppgtt->base.dev))
>               execlists_update_context_pdps(ppgtt, reg_state);
> +
> +     return ce->lrc_desc;
>  }
>  
> -static void execlists_elsp_write(struct drm_i915_gem_request *rq0,
> -                              struct drm_i915_gem_request *rq1)
> +static void execlists_submit_ports(struct intel_engine_cs *engine)
>  {
> -     struct intel_engine_cs *engine = rq0->engine;
> -     struct drm_i915_private *dev_priv = rq0->i915;
> +     struct drm_i915_private *dev_priv = engine->i915;
> +     struct execlist_port *port = engine->execlist_port;
>       u32 __iomem *elsp =
>               dev_priv->regs + i915_mmio_reg_offset(RING_ELSP(engine));
>       u64 desc[2];
>  
> -     if (rq1) {
> -             desc[1] = intel_lr_context_descriptor(rq1->ctx, rq1->engine);
> -             rq1->elsp_submitted++;
> +     if (!port[0].count)
> +             execlists_context_status_change(port[0].request,
> +                                             INTEL_CONTEXT_SCHEDULE_IN);
> +     desc[0] = execlists_update_context(port[0].request);
> +     engine->preempt_wa = port[0].count++; /* bdw only? fixed on skl? */
> +

Experiments show that we need this on gen9 also, even tho some
documentation suggest that we don't.

This one patch took a lot of coffee.

Reviewed-by: Mika Kuoppala <mika.kuopp...@intel.com>

> +     if (port[1].request) {
> +             GEM_BUG_ON(port[1].count);
> +             execlists_context_status_change(port[1].request,
> +                                             INTEL_CONTEXT_SCHEDULE_IN);
> +             desc[1] = execlists_update_context(port[1].request);
> +             port[1].count = 1;
>       } else {
>               desc[1] = 0;
>       }
> -
> -     desc[0] = intel_lr_context_descriptor(rq0->ctx, rq0->engine);
> -     rq0->elsp_submitted++;
> +     GEM_BUG_ON(desc[0] == desc[1]);
>  
>       /* You must always write both descriptors in the order below. */
>       writel(upper_32_bits(desc[1]), elsp);
> @@ -396,141 +407,125 @@ static void execlists_elsp_write(struct 
> drm_i915_gem_request *rq0,
>       writel(lower_32_bits(desc[0]), elsp);
>  }
>  
> -static void execlists_elsp_submit_contexts(struct drm_i915_gem_request *rq0,
> -                                        struct drm_i915_gem_request *rq1)
> +static bool ctx_single_port_submission(const struct i915_gem_context *ctx)
>  {
> -     struct drm_i915_private *dev_priv = rq0->i915;
> -     unsigned int fw_domains = rq0->engine->fw_domains;
> -
> -     execlists_update_context(rq0);
> -
> -     if (rq1)
> -             execlists_update_context(rq1);
> +     return (IS_ENABLED(CONFIG_DRM_I915_GVT) &&
> +             ctx->execlists_force_single_submission);
> +}
>  
> -     spin_lock_irq(&dev_priv->uncore.lock);
> -     intel_uncore_forcewake_get__locked(dev_priv, fw_domains);
> +static bool can_merge_ctx(const struct i915_gem_context *prev,
> +                       const struct i915_gem_context *next)
> +{
> +     if (prev != next)
> +             return false;
>  
> -     execlists_elsp_write(rq0, rq1);
> +     if (ctx_single_port_submission(prev))
> +             return false;
>  
> -     intel_uncore_forcewake_put__locked(dev_priv, fw_domains);
> -     spin_unlock_irq(&dev_priv->uncore.lock);
> +     return true;
>  }
>  
> -static void execlists_unqueue(struct intel_engine_cs *engine)
> +static void execlists_dequeue(struct intel_engine_cs *engine)
>  {
> -     struct drm_i915_gem_request *req0 = NULL, *req1 = NULL;
> -     struct drm_i915_gem_request *cursor, *tmp;
> +     struct drm_i915_gem_request *cursor, *last;
> +     struct execlist_port *port = engine->execlist_port;
> +     bool submit = false;
> +
> +     last = port->request;
> +     if (last)
> +             /* WaIdleLiteRestore:bdw,skl
> +              * Apply the wa NOOPs to prevent ring:HEAD == req:TAIL
> +              * as we resubmit the request. See gen8_emit_request()
> +              * for where we prepare the padding after the end of the
> +              * request.
> +              */
> +             last->tail = last->wa_tail;
>  
> -     assert_spin_locked(&engine->execlist_lock);
> +     GEM_BUG_ON(port[1].request);
>  
> -     /*
> -      * If irqs are not active generate a warning as batches that finish
> -      * without the irqs may get lost and a GPU Hang may occur.
> +     /* Hardware submission is through 2 ports. Conceptually each port
> +      * has a (RING_START, RING_HEAD, RING_TAIL) tuple. RING_START is
> +      * static for a context, and unique to each, so we only execute
> +      * requests belonging to a single context from each ring. RING_HEAD
> +      * is maintained by the CS in the context image, it marks the place
> +      * where it got up to last time, and through RING_TAIL we tell the CS
> +      * where we want to execute up to this time.
> +      *
> +      * In this list the requests are in order of execution. Consecutive
> +      * requests from the same context are adjacent in the ringbuffer. We
> +      * can combine these requests into a single RING_TAIL update:
> +      *
> +      *              RING_HEAD...req1...req2
> +      *                                    ^- RING_TAIL
> +      * since to execute req2 the CS must first execute req1.
> +      *
> +      * Our goal then is to point each port to the end of a consecutive
> +      * sequence of requests as being the most optimal (fewest wake ups
> +      * and context switches) submission.
>        */
> -     WARN_ON(!intel_irqs_enabled(engine->i915));
> -
> -     /* Try to read in pairs */
> -     list_for_each_entry_safe(cursor, tmp, &engine->execlist_queue,
> -                              execlist_link) {
> -             if (!req0) {
> -                     req0 = cursor;
> -             } else if (req0->ctx == cursor->ctx) {
> -                     /* Same ctx: ignore first request, as second request
> -                      * will update tail past first request's workload */
> -                     cursor->elsp_submitted = req0->elsp_submitted;
> -                     list_del(&req0->execlist_link);
> -                     i915_gem_request_put(req0);
> -                     req0 = cursor;
> -             } else {
> -                     if (IS_ENABLED(CONFIG_DRM_I915_GVT)) {
> -                             /*
> -                              * req0 (after merged) ctx requires single
> -                              * submission, stop picking
> -                              */
> -                             if 
> (req0->ctx->execlists_force_single_submission)
> -                                     break;
> -                             /*
> -                              * req0 ctx doesn't require single submission,
> -                              * but next req ctx requires, stop picking
> -                              */
> -                             if 
> (cursor->ctx->execlists_force_single_submission)
> -                                     break;
> -                     }
> -                     req1 = cursor;
> -                     WARN_ON(req1->elsp_submitted);
> -                     break;
> -             }
> -     }
>  
> -     if (unlikely(!req0))
> -             return;
> -
> -     execlists_context_status_change(req0, INTEL_CONTEXT_SCHEDULE_IN);
> -
> -     if (req1)
> -             execlists_context_status_change(req1,
> -                                             INTEL_CONTEXT_SCHEDULE_IN);
> -
> -     if (req0->elsp_submitted & engine->idle_lite_restore_wa) {
> -             /*
> -              * WaIdleLiteRestore: make sure we never cause a lite restore
> -              * with HEAD==TAIL.
> +     spin_lock(&engine->execlist_lock);
> +     list_for_each_entry(cursor, &engine->execlist_queue, execlist_link) {
> +             /* Can we combine this request with the current port? It has to
> +              * be the same context/ringbuffer and not have any exceptions
> +              * (e.g. GVT saying never to combine contexts).
>                *
> -              * Apply the wa NOOPS to prevent ring:HEAD == req:TAIL as we
> -              * resubmit the request. See gen8_emit_request() for where we
> -              * prepare the padding after the end of the request.
> +              * If we can combine the requests, we can execute both by
> +              * updating the RING_TAIL to point to the end of the second
> +              * request, and so we never need to tell the hardware about
> +              * the first.
>                */
> -             req0->tail = req0->wa_tail;
> +             if (last && !can_merge_ctx(cursor->ctx, last->ctx)) {
> +                     /* If we are on the second port and cannot combine
> +                      * this request with the last, then we are done.
> +                      */
> +                     if (port != engine->execlist_port)
> +                             break;
> +
> +                     /* If GVT overrides us we only ever submit port[0],
> +                      * leaving port[1] empty. Note that we also have
> +                      * to be careful that we don't queue the same
> +                      * context (even though a different request) to
> +                      * the second port.
> +                      */
> +                     if (ctx_single_port_submission(cursor->ctx))
> +                             break;
> +
> +                     GEM_BUG_ON(last->ctx == cursor->ctx);
> +
> +                     i915_gem_request_assign(&port->request, last);
> +                     port++;
> +             }
> +             last = cursor;
> +             submit = true;
> +     }
> +     if (submit) {
> +             /* Decouple all the requests submitted from the queue */
> +             engine->execlist_queue.next = &cursor->execlist_link;
> +             cursor->execlist_link.prev = &engine->execlist_queue;
> +
> +             i915_gem_request_assign(&port->request, last);
>       }
> +     spin_unlock(&engine->execlist_lock);
>  
> -     execlists_elsp_submit_contexts(req0, req1);
> +     if (submit)
> +             execlists_submit_ports(engine);
>  }
>  
> -static unsigned int
> -execlists_check_remove_request(struct intel_engine_cs *engine, u32 ctx_id)
> +static bool execlists_elsp_idle(struct intel_engine_cs *engine)
>  {
> -     struct drm_i915_gem_request *head_req;
> -
> -     assert_spin_locked(&engine->execlist_lock);
> -
> -     head_req = list_first_entry_or_null(&engine->execlist_queue,
> -                                         struct drm_i915_gem_request,
> -                                         execlist_link);
> -
> -     if (WARN_ON(!head_req || (head_req->ctx_hw_id != ctx_id)))
> -               return 0;
> -
> -     WARN(head_req->elsp_submitted == 0, "Never submitted head request\n");
> -
> -     if (--head_req->elsp_submitted > 0)
> -             return 0;
> -
> -     execlists_context_status_change(head_req, INTEL_CONTEXT_SCHEDULE_OUT);
> -
> -     list_del(&head_req->execlist_link);
> -     i915_gem_request_put(head_req);
> -
> -     return 1;
> +     return !engine->execlist_port[0].request;
>  }
>  
> -static u32
> -get_context_status(struct intel_engine_cs *engine, unsigned int read_pointer,
> -                u32 *context_id)
> +static bool execlists_elsp_ready(struct intel_engine_cs *engine)
>  {
> -     struct drm_i915_private *dev_priv = engine->i915;
> -     u32 status;
> -
> -     read_pointer %= GEN8_CSB_ENTRIES;
> -
> -     status = I915_READ_FW(RING_CONTEXT_STATUS_BUF_LO(engine, read_pointer));
> -
> -     if (status & GEN8_CTX_STATUS_IDLE_ACTIVE)
> -             return 0;
> +     int port;
>  
> -     *context_id = I915_READ_FW(RING_CONTEXT_STATUS_BUF_HI(engine,
> -                                                           read_pointer));
> +     port = 1; /* wait for a free slot */
> +     if (engine->disable_lite_restore_wa || engine->preempt_wa)
> +             port = 0; /* wait for GPU to be idle before continuing */
>  
> -     return status;
> +     return !engine->execlist_port[port].request;
>  }
>  
>  /*
> @@ -540,67 +535,56 @@ get_context_status(struct intel_engine_cs *engine, 
> unsigned int read_pointer,
>  static void intel_lrc_irq_handler(unsigned long data)
>  {
>       struct intel_engine_cs *engine = (struct intel_engine_cs *)data;
> +     struct execlist_port *port = engine->execlist_port;
>       struct drm_i915_private *dev_priv = engine->i915;
> -     u32 status_pointer;
> -     unsigned int read_pointer, write_pointer;
> -     u32 csb[GEN8_CSB_ENTRIES][2];
> -     unsigned int csb_read = 0, i;
> -     unsigned int submit_contexts = 0;
>  
>       intel_uncore_forcewake_get(dev_priv, engine->fw_domains);
>  
> -     status_pointer = I915_READ_FW(RING_CONTEXT_STATUS_PTR(engine));
> -
> -     read_pointer = engine->next_context_status_buffer;
> -     write_pointer = GEN8_CSB_WRITE_PTR(status_pointer);
> -     if (read_pointer > write_pointer)
> -             write_pointer += GEN8_CSB_ENTRIES;
> -
> -     while (read_pointer < write_pointer) {
> -             if (WARN_ON_ONCE(csb_read == GEN8_CSB_ENTRIES))
> -                     break;
> -             csb[csb_read][0] = get_context_status(engine, ++read_pointer,
> -                                                   &csb[csb_read][1]);
> -             csb_read++;
> -     }
> -
> -     engine->next_context_status_buffer = write_pointer % GEN8_CSB_ENTRIES;
> -
> -     /* Update the read pointer to the old write pointer. Manual ringbuffer
> -      * management ftw </sarcasm> */
> -     I915_WRITE_FW(RING_CONTEXT_STATUS_PTR(engine),
> -                   _MASKED_FIELD(GEN8_CSB_READ_PTR_MASK,
> -                                 engine->next_context_status_buffer << 8));
> -
> -     intel_uncore_forcewake_put(dev_priv, engine->fw_domains);
> -
> -     spin_lock(&engine->execlist_lock);
> +     if (!execlists_elsp_idle(engine)) {
> +             u32 __iomem *csb_mmio =
> +                     dev_priv->regs + 
> i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine));
> +             u32 __iomem *buf =
> +                     dev_priv->regs + 
> i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0));
> +             unsigned int csb, head, tail;
> +
> +             csb = readl(csb_mmio);
> +             head = GEN8_CSB_READ_PTR(csb);
> +             tail = GEN8_CSB_WRITE_PTR(csb);
> +             if (tail < head)
> +                     tail += GEN8_CSB_ENTRIES;
> +             while (head < tail) {
> +                     unsigned int idx = ++head % GEN8_CSB_ENTRIES;
> +                     unsigned int status = readl(buf + 2 * idx);
> +
> +                     if (!(status & GEN8_CTX_STATUS_COMPLETED_MASK))
> +                             continue;
> +
> +                     GEM_BUG_ON(port[0].count == 0);
> +                     if (--port[0].count == 0) {
> +                             GEM_BUG_ON(status & GEN8_CTX_STATUS_PREEMPTED);
> +                             execlists_context_status_change(port[0].request,
> +                                                             
> INTEL_CONTEXT_SCHEDULE_OUT);
> +
> +                             i915_gem_request_put(port[0].request);
> +                             port[0] = port[1];
> +                             memset(&port[1], 0, sizeof(port[1]));
> +
> +                             engine->preempt_wa = false;
> +                     }
>  
> -     for (i = 0; i < csb_read; i++) {
> -             if (unlikely(csb[i][0] & GEN8_CTX_STATUS_PREEMPTED)) {
> -                     if (csb[i][0] & GEN8_CTX_STATUS_LITE_RESTORE) {
> -                             if (execlists_check_remove_request(engine, 
> csb[i][1]))
> -                                     WARN(1, "Lite Restored request removed 
> from queue\n");
> -                     } else
> -                             WARN(1, "Preemption without Lite Restore\n");
> +                     GEM_BUG_ON(port[0].count == 0 &&
> +                                !(status & GEN8_CTX_STATUS_ACTIVE_IDLE));
>               }
>  
> -             if (csb[i][0] & (GEN8_CTX_STATUS_ACTIVE_IDLE |
> -                 GEN8_CTX_STATUS_ELEMENT_SWITCH))
> -                     submit_contexts +=
> -                             execlists_check_remove_request(engine, 
> csb[i][1]);
> +             writel(_MASKED_FIELD(GEN8_CSB_READ_PTR_MASK,
> +                                  GEN8_CSB_WRITE_PTR(csb) << 8),
> +                    csb_mmio);
>       }
>  
> -     if (submit_contexts) {
> -             if (!engine->disable_lite_restore_wa ||
> -                 (csb[i][0] & GEN8_CTX_STATUS_ACTIVE_IDLE))
> -                     execlists_unqueue(engine);
> -     }
> +     if (execlists_elsp_ready(engine))
> +             execlists_dequeue(engine);
>  
> -     spin_unlock(&engine->execlist_lock);
> -
> -     if (unlikely(submit_contexts > 2))
> -             DRM_ERROR("More than two context complete events?\n");
> +     intel_uncore_forcewake_put(dev_priv, engine->fw_domains);
>  }
>  
>  static void execlists_submit_request(struct drm_i915_gem_request *request)
> @@ -609,12 +593,9 @@ static void execlists_submit_request(struct 
> drm_i915_gem_request *request)
>  
>       spin_lock_bh(&engine->execlist_lock);
>  
> -     i915_gem_request_get(request);
> -     request->ctx_hw_id = request->ctx->hw_id;
> -
> -     if (list_empty(&engine->execlist_queue))
> -             tasklet_hi_schedule(&engine->irq_tasklet);
>       list_add_tail(&request->execlist_link, &engine->execlist_queue);
> +     if (execlists_elsp_idle(engine))
> +             tasklet_hi_schedule(&engine->irq_tasklet);
>  
>       spin_unlock_bh(&engine->execlist_lock);
>  }
> @@ -721,23 +702,6 @@ intel_logical_ring_advance(struct drm_i915_gem_request 
> *request)
>       return 0;
>  }
>  
> -void intel_execlists_cancel_requests(struct intel_engine_cs *engine)
> -{
> -     struct drm_i915_gem_request *req, *tmp;
> -     LIST_HEAD(cancel_list);
> -
> -     WARN_ON(!mutex_is_locked(&engine->i915->drm.struct_mutex));
> -
> -     spin_lock_bh(&engine->execlist_lock);
> -     list_replace_init(&engine->execlist_queue, &cancel_list);
> -     spin_unlock_bh(&engine->execlist_lock);
> -
> -     list_for_each_entry_safe(req, tmp, &cancel_list, execlist_link) {
> -             list_del(&req->execlist_link);
> -             i915_gem_request_put(req);
> -     }
> -}
> -
>  static int intel_lr_context_pin(struct i915_gem_context *ctx,
>                               struct intel_engine_cs *engine)
>  {
> @@ -1258,7 +1222,6 @@ static void lrc_init_hws(struct intel_engine_cs *engine)
>  static int gen8_init_common_ring(struct intel_engine_cs *engine)
>  {
>       struct drm_i915_private *dev_priv = engine->i915;
> -     unsigned int next_context_status_buffer_hw;
>  
>       lrc_init_hws(engine);
>  
> @@ -1269,32 +1232,12 @@ static int gen8_init_common_ring(struct 
> intel_engine_cs *engine)
>       I915_WRITE(RING_MODE_GEN7(engine),
>                  _MASKED_BIT_DISABLE(GFX_REPLAY_MODE) |
>                  _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE));
> -     POSTING_READ(RING_MODE_GEN7(engine));
>  
> -     /*
> -      * Instead of resetting the Context Status Buffer (CSB) read pointer to
> -      * zero, we need to read the write pointer from hardware and use its
> -      * value because "this register is power context save restored".
> -      * Effectively, these states have been observed:
> -      *
> -      *      | Suspend-to-idle (freeze) | Suspend-to-RAM (mem) |
> -      * BDW  | CSB regs not reset       | CSB regs reset       |
> -      * CHT  | CSB regs not reset       | CSB regs not reset   |
> -      * SKL  |         ?                |         ?            |
> -      * BXT  |         ?                |         ?            |
> -      */
> -     next_context_status_buffer_hw =
> -             GEN8_CSB_WRITE_PTR(I915_READ(RING_CONTEXT_STATUS_PTR(engine)));
> +     I915_WRITE(RING_CONTEXT_STATUS_PTR(engine),
> +                _MASKED_FIELD(GEN8_CSB_READ_PTR_MASK |
> +                              GEN8_CSB_WRITE_PTR_MASK,
> +                              0));
>  
> -     /*
> -      * When the CSB registers are reset (also after power-up / gpu reset),
> -      * CSB write pointer is set to all 1's, which is not valid, use '5' in
> -      * this special case, so the first element read is CSB[0].
> -      */
> -     if (next_context_status_buffer_hw == GEN8_CSB_PTR_MASK)
> -             next_context_status_buffer_hw = (GEN8_CSB_ENTRIES - 1);
> -
> -     engine->next_context_status_buffer = next_context_status_buffer_hw;
>       DRM_DEBUG_DRIVER("Execlists enabled for %s\n", engine->name);
>  
>       intel_engine_init_hangcheck(engine);
> @@ -1680,10 +1623,6 @@ void intel_logical_ring_cleanup(struct intel_engine_cs 
> *engine)
>       }
>       intel_lr_context_unpin(dev_priv->kernel_context, engine);
>  
> -     engine->idle_lite_restore_wa = 0;
> -     engine->disable_lite_restore_wa = false;
> -     engine->ctx_desc_template = 0;
> -
>       lrc_destroy_wa_ctx_obj(engine);
>       engine->i915 = NULL;
>  }
> diff --git a/drivers/gpu/drm/i915/intel_lrc.h 
> b/drivers/gpu/drm/i915/intel_lrc.h
> index a52cf57dbd40..4d70346500c2 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.h
> +++ b/drivers/gpu/drm/i915/intel_lrc.h
> @@ -97,6 +97,4 @@ int intel_sanitize_enable_execlists(struct drm_i915_private 
> *dev_priv,
>                                   int enable_execlists);
>  void intel_execlists_enable_submission(struct drm_i915_private *dev_priv);
>  
> -void intel_execlists_cancel_requests(struct intel_engine_cs *engine);
> -
>  #endif /* _INTEL_LRC_H_ */
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h 
> b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 84aea549de5d..2181d0a41a96 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -298,11 +298,14 @@ struct intel_engine_cs {
>       /* Execlists */
>       struct tasklet_struct irq_tasklet;
>       spinlock_t execlist_lock; /* used inside tasklet, use spin_lock_bh */
> +     struct execlist_port {
> +             struct drm_i915_gem_request *request;
> +             unsigned int count;
> +     } execlist_port[2];
>       struct list_head execlist_queue;
>       unsigned int fw_domains;
> -     unsigned int next_context_status_buffer;
> -     unsigned int idle_lite_restore_wa;
>       bool disable_lite_restore_wa;
> +     bool preempt_wa;
>       u32 ctx_desc_template;
>  
>       /**
> -- 
> 2.9.3
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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