alistair23-linux/drivers/gpu/drm/i915/intel_ringbuffer.h
Chris Wilson c7dca47bd6 drm/i915/ringbuffer: Fix use of stale HEAD position whilst polling for space
During suspend, Linus found that his machine would hang for 3 seconds,
and identified that intel_ring_buffer_wait() was the culprit:

"Because from looking at the code, I get the notion that
"intel_read_status_page()" may not be exact. But what happens if that
inexact value matches our cached ring->actual_head, so we never even
try to read the exact case? Does it _stay_ inexact for arbitrarily
long times? If so, we might wait for the ring to empty forever (well,
until the timeout - the behavior I see), even though the ring really
_is_ empty."

As the reported HEAD position is only updated every time it crosses a
64k boundary, whilst draining the ring it is indeed likely to remain one
value. If that value matches the last known HEAD position, we never read
the true value from the register and so trigger a timeout.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2011-01-20 17:26:57 +00:00

173 lines
4.8 KiB
C

#ifndef _INTEL_RINGBUFFER_H_
#define _INTEL_RINGBUFFER_H_
enum {
RCS = 0x0,
VCS,
BCS,
I915_NUM_RINGS,
};
struct intel_hw_status_page {
u32 __iomem *page_addr;
unsigned int gfx_addr;
struct drm_i915_gem_object *obj;
};
#define I915_RING_READ(reg) i915_safe_read(dev_priv, reg)
#define I915_READ_TAIL(ring) I915_RING_READ(RING_TAIL((ring)->mmio_base))
#define I915_WRITE_TAIL(ring, val) I915_WRITE(RING_TAIL((ring)->mmio_base), val)
#define I915_READ_START(ring) I915_RING_READ(RING_START((ring)->mmio_base))
#define I915_WRITE_START(ring, val) I915_WRITE(RING_START((ring)->mmio_base), val)
#define I915_READ_HEAD(ring) I915_RING_READ(RING_HEAD((ring)->mmio_base))
#define I915_WRITE_HEAD(ring, val) I915_WRITE(RING_HEAD((ring)->mmio_base), val)
#define I915_READ_CTL(ring) I915_RING_READ(RING_CTL((ring)->mmio_base))
#define I915_WRITE_CTL(ring, val) I915_WRITE(RING_CTL((ring)->mmio_base), val)
#define I915_WRITE_IMR(ring, val) I915_WRITE(RING_IMR((ring)->mmio_base), val)
#define I915_READ_IMR(ring) I915_RING_READ(RING_IMR((ring)->mmio_base))
#define I915_READ_NOPID(ring) I915_RING_READ(RING_NOPID((ring)->mmio_base))
#define I915_READ_SYNC_0(ring) I915_RING_READ(RING_SYNC_0((ring)->mmio_base))
#define I915_READ_SYNC_1(ring) I915_RING_READ(RING_SYNC_1((ring)->mmio_base))
struct intel_ring_buffer {
const char *name;
enum intel_ring_id {
RING_RENDER = 0x1,
RING_BSD = 0x2,
RING_BLT = 0x4,
} id;
u32 mmio_base;
void *virtual_start;
struct drm_device *dev;
struct drm_i915_gem_object *obj;
u32 head;
u32 tail;
int space;
int size;
int effective_size;
struct intel_hw_status_page status_page;
spinlock_t irq_lock;
u32 irq_refcount;
u32 irq_mask;
u32 irq_seqno; /* last seq seem at irq time */
u32 waiting_seqno;
u32 sync_seqno[I915_NUM_RINGS-1];
bool __must_check (*irq_get)(struct intel_ring_buffer *ring);
void (*irq_put)(struct intel_ring_buffer *ring);
int (*init)(struct intel_ring_buffer *ring);
void (*write_tail)(struct intel_ring_buffer *ring,
u32 value);
int __must_check (*flush)(struct intel_ring_buffer *ring,
u32 invalidate_domains,
u32 flush_domains);
int (*add_request)(struct intel_ring_buffer *ring,
u32 *seqno);
u32 (*get_seqno)(struct intel_ring_buffer *ring);
int (*dispatch_execbuffer)(struct intel_ring_buffer *ring,
u32 offset, u32 length);
void (*cleanup)(struct intel_ring_buffer *ring);
/**
* List of objects currently involved in rendering from the
* ringbuffer.
*
* Includes buffers having the contents of their GPU caches
* flushed, not necessarily primitives. last_rendering_seqno
* represents when the rendering involved will be completed.
*
* A reference is held on the buffer while on this list.
*/
struct list_head active_list;
/**
* List of breadcrumbs associated with GPU requests currently
* outstanding.
*/
struct list_head request_list;
/**
* List of objects currently pending a GPU write flush.
*
* All elements on this list will belong to either the
* active_list or flushing_list, last_rendering_seqno can
* be used to differentiate between the two elements.
*/
struct list_head gpu_write_list;
/**
* Do we have some not yet emitted requests outstanding?
*/
u32 outstanding_lazy_request;
wait_queue_head_t irq_queue;
drm_local_map_t map;
void *private;
};
static inline u32
intel_ring_sync_index(struct intel_ring_buffer *ring,
struct intel_ring_buffer *other)
{
int idx;
/*
* cs -> 0 = vcs, 1 = bcs
* vcs -> 0 = bcs, 1 = cs,
* bcs -> 0 = cs, 1 = vcs.
*/
idx = (other - ring) - 1;
if (idx < 0)
idx += I915_NUM_RINGS;
return idx;
}
static inline u32
intel_read_status_page(struct intel_ring_buffer *ring,
int reg)
{
return ioread32(ring->status_page.page_addr + reg);
}
void intel_cleanup_ring_buffer(struct intel_ring_buffer *ring);
int __must_check intel_wait_ring_buffer(struct intel_ring_buffer *ring, int n);
int __must_check intel_ring_begin(struct intel_ring_buffer *ring, int n);
static inline void intel_ring_emit(struct intel_ring_buffer *ring,
u32 data)
{
iowrite32(data, ring->virtual_start + ring->tail);
ring->tail += 4;
}
void intel_ring_advance(struct intel_ring_buffer *ring);
u32 intel_ring_get_seqno(struct intel_ring_buffer *ring);
int intel_ring_sync(struct intel_ring_buffer *ring,
struct intel_ring_buffer *to,
u32 seqno);
int intel_init_render_ring_buffer(struct drm_device *dev);
int intel_init_bsd_ring_buffer(struct drm_device *dev);
int intel_init_blt_ring_buffer(struct drm_device *dev);
u32 intel_ring_get_active_head(struct intel_ring_buffer *ring);
void intel_ring_setup_status_page(struct intel_ring_buffer *ring);
/* DRI warts */
int intel_render_ring_init_dri(struct drm_device *dev, u64 start, u32 size);
#endif /* _INTEL_RINGBUFFER_H_ */