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drm/i915/bdw: Handle context switch events 

Handle all context status events in the context status buffer on every
context switch interrupt. We only remove work from the execlist queue
after a context status buffer reports that it has completed and we only
attempt to schedule new contexts on interrupt when a previously submitted
context completes (unless no contexts are queued, which means the GPU is
free).

We canot call intel_runtime_pm_get() in an interrupt (or with a spinlock
grabbed, FWIW), because it might sleep, which is not a nice thing to do.
Instead, do the runtime_pm get/put together with the create/destroy request,
and handle the forcewake get/put directly.

Signed-off-by: Thomas Daniel <thomas.daniel@intel.com>

v2: Unreferencing the context when we are freeing the request might free
the backing bo, which requires the struct_mutex to be grabbed, so defer
unreferencing and freeing to a bottom half.

v3:
- Ack the interrupt inmediately, before trying to handle it (fix for
missing interrupts by Bob Beckett <robert.beckett@intel.com>).
- Update the Context Status Buffer Read Pointer, just in case (spotted
by Damien Lespiau).

v4: New namespace and multiple rebase changes.

v5: Squash with "drm/i915/bdw: Do not call intel_runtime_pm_get() in an
interrupt", as suggested by Daniel.

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Checkpatch ...]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Thomas Daniel 2014-07-24 17:04:39 +01:00 committed by Daniel Vetter
parent acdd884a2e
commit e981e7b17f
4 changed files with 155 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
drivers/gpu/drm/i915/i915_irq.c
View File

@ -1632,6 +1632,7 @@ static irqreturn_t gen8_gt_irq_handler(struct drm_device *dev,
struct drm_i915_private *dev_priv,
u32 master_ctl)
{
struct intel_engine_cs *ring;
u32 rcs, bcs, vcs;
uint32_t tmp = 0;
irqreturn_t ret = IRQ_NONE;
@ -1641,14 +1642,20 @@ static irqreturn_t gen8_gt_irq_handler(struct drm_device *dev,
if (tmp) {
I915_WRITE(GEN8_GT_IIR(0), tmp);
ret = IRQ_HANDLED;
rcs = tmp >> GEN8_RCS_IRQ_SHIFT;
bcs = tmp >> GEN8_BCS_IRQ_SHIFT;
ring = &dev_priv->ring[RCS];
if (rcs & GT_RENDER_USER_INTERRUPT)
notify_ring(dev, &dev_priv->ring[RCS]);
notify_ring(dev, ring);
if (rcs & GT_CONTEXT_SWITCH_INTERRUPT)
intel_execlists_handle_ctx_events(ring);
bcs = tmp >> GEN8_BCS_IRQ_SHIFT;
ring = &dev_priv->ring[BCS];
if (bcs & GT_RENDER_USER_INTERRUPT)
notify_ring(dev, &dev_priv->ring[BCS]);
if ((rcs | bcs) & GT_CONTEXT_SWITCH_INTERRUPT)
DRM_DEBUG_DRIVER("TODO: Context switch\n");
notify_ring(dev, ring);
if (bcs & GT_CONTEXT_SWITCH_INTERRUPT)
intel_execlists_handle_ctx_events(ring);
} else
DRM_ERROR("The master control interrupt lied (GT0)!\n");
}
@ -1658,16 +1665,20 @@ static irqreturn_t gen8_gt_irq_handler(struct drm_device *dev,
if (tmp) {
I915_WRITE(GEN8_GT_IIR(1), tmp);
ret = IRQ_HANDLED;
vcs = tmp >> GEN8_VCS1_IRQ_SHIFT;
ring = &dev_priv->ring[VCS];
if (vcs & GT_RENDER_USER_INTERRUPT)
notify_ring(dev, &dev_priv->ring[VCS]);
notify_ring(dev, ring);
if (vcs & GT_CONTEXT_SWITCH_INTERRUPT)
DRM_DEBUG_DRIVER("TODO: Context switch\n");
intel_execlists_handle_ctx_events(ring);
vcs = tmp >> GEN8_VCS2_IRQ_SHIFT;
ring = &dev_priv->ring[VCS2];
if (vcs & GT_RENDER_USER_INTERRUPT)
notify_ring(dev, &dev_priv->ring[VCS2]);
notify_ring(dev, ring);
if (vcs & GT_CONTEXT_SWITCH_INTERRUPT)
DRM_DEBUG_DRIVER("TODO: Context switch\n");
intel_execlists_handle_ctx_events(ring);
} else
DRM_ERROR("The master control interrupt lied (GT1)!\n");
}
@ -1688,11 +1699,13 @@ static irqreturn_t gen8_gt_irq_handler(struct drm_device *dev,
if (tmp) {
I915_WRITE(GEN8_GT_IIR(3), tmp);
ret = IRQ_HANDLED;
vcs = tmp >> GEN8_VECS_IRQ_SHIFT;
ring = &dev_priv->ring[VECS];
if (vcs & GT_RENDER_USER_INTERRUPT)
notify_ring(dev, &dev_priv->ring[VECS]);
notify_ring(dev, ring);
if (vcs & GT_CONTEXT_SWITCH_INTERRUPT)
DRM_DEBUG_DRIVER("TODO: Context switch\n");
intel_execlists_handle_ctx_events(ring);
} else
DRM_ERROR("The master control interrupt lied (GT3)!\n");
}

133
drivers/gpu/drm/i915/intel_lrc.c
View File

@ -49,6 +49,22 @@
#define RING_ELSP(ring) ((ring)->mmio_base+0x230)
#define RING_EXECLIST_STATUS(ring) ((ring)->mmio_base+0x234)
#define RING_CONTEXT_CONTROL(ring) ((ring)->mmio_base+0x244)
#define RING_CONTEXT_STATUS_BUF(ring) ((ring)->mmio_base+0x370)
#define RING_CONTEXT_STATUS_PTR(ring) ((ring)->mmio_base+0x3a0)
#define RING_EXECLIST_QFULL (1 << 0x2)
#define RING_EXECLIST1_VALID (1 << 0x3)
#define RING_EXECLIST0_VALID (1 << 0x4)
#define RING_EXECLIST_ACTIVE_STATUS (3 << 0xE)
#define RING_EXECLIST1_ACTIVE (1 << 0x11)
#define RING_EXECLIST0_ACTIVE (1 << 0x12)
#define GEN8_CTX_STATUS_IDLE_ACTIVE (1 << 0)
#define GEN8_CTX_STATUS_PREEMPTED (1 << 1)
#define GEN8_CTX_STATUS_ELEMENT_SWITCH (1 << 2)
#define GEN8_CTX_STATUS_ACTIVE_IDLE (1 << 3)
#define GEN8_CTX_STATUS_COMPLETE (1 << 4)
#define GEN8_CTX_STATUS_LITE_RESTORE (1 << 15)
#define CTX_LRI_HEADER_0 0x01
#define CTX_CONTEXT_CONTROL 0x02
@ -150,6 +166,7 @@ static void execlists_elsp_write(struct intel_engine_cs *ring,
struct drm_i915_private *dev_priv = ring->dev->dev_private;
uint64_t temp = 0;
uint32_t desc[4];
unsigned long flags;
/* XXX: You must always write both descriptors in the order below. */
if (ctx_obj1)
@ -163,9 +180,17 @@ static void execlists_elsp_write(struct intel_engine_cs *ring,
desc[3] = (u32)(temp >> 32);
desc[2] = (u32)temp;
/* Set Force Wakeup bit to prevent GT from entering C6 while
* ELSP writes are in progress */
gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL);
/* Set Force Wakeup bit to prevent GT from entering C6 while ELSP writes
* are in progress.
*
* The other problem is that we can't just call gen6_gt_force_wake_get()
* because that function calls intel_runtime_pm_get(), which might sleep.
* Instead, we do the runtime_pm_get/put when creating/destroying requests.
*/
spin_lock_irqsave(&dev_priv->uncore.lock, flags);
if (dev_priv->uncore.forcewake_count++ == 0)
dev_priv->uncore.funcs.force_wake_get(dev_priv, FORCEWAKE_ALL);
spin_unlock_irqrestore(&dev_priv->uncore.lock, flags);
I915_WRITE(RING_ELSP(ring), desc[1]);
I915_WRITE(RING_ELSP(ring), desc[0]);
@ -176,7 +201,11 @@ static void execlists_elsp_write(struct intel_engine_cs *ring,
/* ELSP is a wo register, so use another nearby reg for posting instead */
POSTING_READ(RING_EXECLIST_STATUS(ring));
gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
/* Release Force Wakeup (see the big comment above). */
spin_lock_irqsave(&dev_priv->uncore.lock, flags);
if (--dev_priv->uncore.forcewake_count == 0)
dev_priv->uncore.funcs.force_wake_put(dev_priv, FORCEWAKE_ALL);
spin_unlock_irqrestore(&dev_priv->uncore.lock, flags);
}
static int execlists_ctx_write_tail(struct drm_i915_gem_object *ctx_obj, u32 tail)
@ -224,6 +253,9 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring)
{
struct intel_ctx_submit_request *req0 = NULL, *req1 = NULL;
struct intel_ctx_submit_request *cursor = NULL, *tmp = NULL;
struct drm_i915_private *dev_priv = ring->dev->dev_private;
assert_spin_locked(&ring->execlist_lock);
if (list_empty(&ring->execlist_queue))
return;
@ -237,8 +269,7 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring)
/* Same ctx: ignore first request, as second request
* will update tail past first request's workload */
list_del(&req0->execlist_link);
i915_gem_context_unreference(req0->ctx);
kfree(req0);
queue_work(dev_priv->wq, &req0->work);
req0 = cursor;
} else {
req1 = cursor;
@ -251,11 +282,97 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring)
req1 ? req1->tail : 0));
}
static bool execlists_check_remove_request(struct intel_engine_cs *ring,
u32 request_id)
{
struct drm_i915_private *dev_priv = ring->dev->dev_private;
struct intel_ctx_submit_request *head_req;
assert_spin_locked(&ring->execlist_lock);
head_req = list_first_entry_or_null(&ring->execlist_queue,
struct intel_ctx_submit_request,
execlist_link);
if (head_req != NULL) {
struct drm_i915_gem_object *ctx_obj =
head_req->ctx->engine[ring->id].state;
if (intel_execlists_ctx_id(ctx_obj) == request_id) {
list_del(&head_req->execlist_link);
queue_work(dev_priv->wq, &head_req->work);
return true;
}
}
return false;
}
void intel_execlists_handle_ctx_events(struct intel_engine_cs *ring)
{
struct drm_i915_private *dev_priv = ring->dev->dev_private;
u32 status_pointer;
u8 read_pointer;
u8 write_pointer;
u32 status;
u32 status_id;
u32 submit_contexts = 0;
status_pointer = I915_READ(RING_CONTEXT_STATUS_PTR(ring));
read_pointer = ring->next_context_status_buffer;
write_pointer = status_pointer & 0x07;
if (read_pointer > write_pointer)
write_pointer += 6;
spin_lock(&ring->execlist_lock);
while (read_pointer < write_pointer) {
read_pointer++;
status = I915_READ(RING_CONTEXT_STATUS_BUF(ring) +
(read_pointer % 6) * 8);
status_id = I915_READ(RING_CONTEXT_STATUS_BUF(ring) +
(read_pointer % 6) * 8 + 4);
if (status & GEN8_CTX_STATUS_COMPLETE) {
if (execlists_check_remove_request(ring, status_id))
submit_contexts++;
}
}
if (submit_contexts != 0)
execlists_context_unqueue(ring);
spin_unlock(&ring->execlist_lock);
WARN(submit_contexts > 2, "More than two context complete events?\n");
ring->next_context_status_buffer = write_pointer % 6;
I915_WRITE(RING_CONTEXT_STATUS_PTR(ring),
((u32)ring->next_context_status_buffer & 0x07) << 8);
}
static void execlists_free_request_task(struct work_struct *work)
{
struct intel_ctx_submit_request *req =
container_of(work, struct intel_ctx_submit_request, work);
struct drm_device *dev = req->ring->dev;
struct drm_i915_private *dev_priv = dev->dev_private;
intel_runtime_pm_put(dev_priv);
mutex_lock(&dev->struct_mutex);
i915_gem_context_unreference(req->ctx);
mutex_unlock(&dev->struct_mutex);
kfree(req);
}
static int execlists_context_queue(struct intel_engine_cs *ring,
struct intel_context *to,
u32 tail)
{
struct intel_ctx_submit_request *req = NULL;
struct drm_i915_private *dev_priv = ring->dev->dev_private;
unsigned long flags;
bool was_empty;
@ -266,6 +383,9 @@ static int execlists_context_queue(struct intel_engine_cs *ring,
i915_gem_context_reference(req->ctx);
req->ring = ring;
req->tail = tail;
INIT_WORK(&req->work, execlists_free_request_task);
intel_runtime_pm_get(dev_priv);
spin_lock_irqsave(&ring->execlist_lock, flags);
@ -907,6 +1027,7 @@ static int logical_ring_init(struct drm_device *dev, struct intel_engine_cs *rin
INIT_LIST_HEAD(&ring->execlist_queue);
spin_lock_init(&ring->execlist_lock);
ring->next_context_status_buffer = 0;
ret = intel_lr_context_deferred_create(dctx, ring);
if (ret)

3
drivers/gpu/drm/i915/intel_lrc.h
View File

@ -65,6 +65,9 @@ struct intel_ctx_submit_request {
u32 tail;
struct list_head execlist_link;
struct work_struct work;
};
void intel_execlists_handle_ctx_events(struct intel_engine_cs *ring);
#endif /* _INTEL_LRC_H_ */

1
drivers/gpu/drm/i915/intel_ringbuffer.h
View File

@ -233,6 +233,7 @@ struct intel_engine_cs {
/* Execlists */
spinlock_t execlist_lock;
struct list_head execlist_queue;
u8 next_context_status_buffer;
u32 irq_keep_mask; /* bitmask for interrupts that should not be masked */
int (*emit_request)(struct intel_ringbuffer *ringbuf);
int (*emit_flush)(struct intel_ringbuffer *ringbuf,