void
i915_kernel_lost_context(struct drm_device * dev)
{
drm_i915_private_t *dev_priv = dev->dev_private;
#if 0
struct drm_i915_master_private *master_priv;
#endif
struct intel_ring_buffer *ring = LP_RING(dev_priv);
/*
* We should never lose context on the ring with modesetting
* as we don't expose it to userspace
*/
if (drm_core_check_feature(dev, DRIVER_MODESET))
return;
ring->head = I915_READ_HEAD(ring) & HEAD_ADDR;
ring->tail = I915_READ_TAIL(ring) & TAIL_ADDR;
ring->space = ring->head - (ring->tail + I915_RING_FREE_SPACE);
if (ring->space < 0)
ring->space += ring->size;
#if 0
if (!dev->primary->master)
return;
master_priv = dev->primary->master->driver_priv;
if (ring->head == ring->tail && master_priv->sarea_priv)
master_priv->sarea_priv->perf_boxes |= I915_BOX_RING_EMPTY;
#endif
}
static int init_ring_common(struct intel_ring_buffer *ring)
{
drm_i915_private_t *dev_priv = ring->dev->dev_private;
struct drm_i915_gem_object *obj = ring->obj;
u32 head;
/* Stop the ring if it's running. */
I915_WRITE_CTL(ring, 0);
I915_WRITE_HEAD(ring, 0);
ring->write_tail(ring, 0);
/* Initialize the ring. */
I915_WRITE_START(ring, obj->gtt_offset);
head = I915_READ_HEAD(ring) & HEAD_ADDR;
/* G45 ring initialization fails to reset head to zero */
if (head != 0) {
DRM_DEBUG_KMS("%s head not reset to zero "
"ctl %08x head %08x tail %08x start %08x\n",
ring->name,
I915_READ_CTL(ring),
I915_READ_HEAD(ring),
I915_READ_TAIL(ring),
I915_READ_START(ring));
I915_WRITE_HEAD(ring, 0);
if (I915_READ_HEAD(ring) & HEAD_ADDR) {
DRM_ERROR("failed to set %s head to zero "
"ctl %08x head %08x tail %08x start %08x\n",
ring->name,
I915_READ_CTL(ring),
I915_READ_HEAD(ring),
I915_READ_TAIL(ring),
I915_READ_START(ring));
}
}
I915_WRITE_CTL(ring,
((ring->size - PAGE_SIZE) & RING_NR_PAGES)
| RING_REPORT_64K | RING_VALID);
/* If the head is still not zero, the ring is dead */
if ((I915_READ_CTL(ring) & RING_VALID) == 0 ||
I915_READ_START(ring) != obj->gtt_offset ||
(I915_READ_HEAD(ring) & HEAD_ADDR) != 0) {
DRM_ERROR("%s initialization failed "
"ctl %08x head %08x tail %08x start %08x\n",
ring->name,
I915_READ_CTL(ring),
I915_READ_HEAD(ring),
I915_READ_TAIL(ring),
I915_READ_START(ring));
return -EIO;
}
if (!drm_core_check_feature(ring->dev, DRIVER_MODESET))
i915_kernel_lost_context(ring->dev);
else {
ring->head = I915_READ_HEAD(ring);
ring->tail = I915_READ_TAIL(ring) & TAIL_ADDR;
ring->space = ring_space(ring);
}
return 0;
}
static struct intel_engine_cs *
semaphore_waits_for(struct intel_engine_cs *engine, u32 *seqno)
{
struct drm_i915_private *dev_priv = engine->i915;
void __iomem *vaddr;
u32 cmd, ipehr, head;
u64 offset = 0;
int i, backwards;
/*
* This function does not support execlist mode - any attempt to
* proceed further into this function will result in a kernel panic
* when dereferencing ring->buffer, which is not set up in execlist
* mode.
*
* The correct way of doing it would be to derive the currently
* executing ring buffer from the current context, which is derived
* from the currently running request. Unfortunately, to get the
* current request we would have to grab the struct_mutex before doing
* anything else, which would be ill-advised since some other thread
* might have grabbed it already and managed to hang itself, causing
* the hang checker to deadlock.
*
* Therefore, this function does not support execlist mode in its
* current form. Just return NULL and move on.
*/
if (engine->buffer == NULL)
return NULL;
ipehr = I915_READ(RING_IPEHR(engine->mmio_base));
if (!ipehr_is_semaphore_wait(engine, ipehr))
return NULL;
/*
* HEAD is likely pointing to the dword after the actual command,
* so scan backwards until we find the MBOX. But limit it to just 3
* or 4 dwords depending on the semaphore wait command size.
* Note that we don't care about ACTHD here since that might
* point at at batch, and semaphores are always emitted into the
* ringbuffer itself.
*/
head = I915_READ_HEAD(engine) & HEAD_ADDR;
backwards = (INTEL_GEN(dev_priv) >= 8) ? 5 : 4;
vaddr = (void __iomem *)engine->buffer->vaddr;
for (i = backwards; i; --i) {
/*
* Be paranoid and presume the hw has gone off into the wild -
* our ring is smaller than what the hardware (and hence
* HEAD_ADDR) allows. Also handles wrap-around.
*/
head &= engine->buffer->size - 1;
/* This here seems to blow up */
cmd = ioread32(vaddr + head);
if (cmd == ipehr)
break;
head -= 4;
}
if (!i)
return NULL;
*seqno = ioread32(vaddr + head + 4) + 1;
return semaphore_wait_to_signaller_ring(engine, ipehr, offset);
}
