blob: 6b2067f1082402bf0f5598dda62fa1c28531fa0d [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/hashtable.h>
#include "i915_gem_batch_pool.h"
#include "i915_gem_request.h"
#include "i915_gem_timeline.h"
#include "i915_selftest.h"
#define I915_CMD_HASH_ORDER 9
/* Early gen2 devices have a cacheline of just 32 bytes, using 64 is overkill,
* but keeps the logic simple. Indeed, the whole purpose of this macro is just
* to give some inclination as to some of the magic values used in the various
* workarounds!
#define CACHELINE_DWORDS (CACHELINE_BYTES / sizeof(uint32_t))
struct intel_hw_status_page {
struct i915_vma *vma;
u32 *page_addr;
u32 ggtt_offset;
#define I915_READ_TAIL(engine) I915_READ(RING_TAIL((engine)->mmio_base))
#define I915_WRITE_TAIL(engine, val) I915_WRITE(RING_TAIL((engine)->mmio_base), val)
#define I915_READ_START(engine) I915_READ(RING_START((engine)->mmio_base))
#define I915_WRITE_START(engine, val) I915_WRITE(RING_START((engine)->mmio_base), val)
#define I915_READ_HEAD(engine) I915_READ(RING_HEAD((engine)->mmio_base))
#define I915_WRITE_HEAD(engine, val) I915_WRITE(RING_HEAD((engine)->mmio_base), val)
#define I915_READ_CTL(engine) I915_READ(RING_CTL((engine)->mmio_base))
#define I915_WRITE_CTL(engine, val) I915_WRITE(RING_CTL((engine)->mmio_base), val)
#define I915_READ_IMR(engine) I915_READ(RING_IMR((engine)->mmio_base))
#define I915_WRITE_IMR(engine, val) I915_WRITE(RING_IMR((engine)->mmio_base), val)
#define I915_READ_MODE(engine) I915_READ(RING_MI_MODE((engine)->mmio_base))
#define I915_WRITE_MODE(engine, val) I915_WRITE(RING_MI_MODE((engine)->mmio_base), val)
/* seqno size is actually only a uint32, but since we plan to use MI_FLUSH_DW to
* do the writes, and that must have qw aligned offsets, simply pretend it's 8b.
#define gen8_semaphore_seqno_size sizeof(uint64_t)
#define GEN8_SEMAPHORE_OFFSET(__from, __to) \
(((__from) * I915_NUM_ENGINES + (__to)) * gen8_semaphore_seqno_size)
#define GEN8_SIGNAL_OFFSET(__ring, to) \
(dev_priv->semaphore->node.start + \
GEN8_SEMAPHORE_OFFSET((__ring)->id, (to)))
#define GEN8_WAIT_OFFSET(__ring, from) \
(dev_priv->semaphore->node.start + \
GEN8_SEMAPHORE_OFFSET(from, (__ring)->id))
enum intel_engine_hangcheck_action {
static inline const char *
hangcheck_action_to_str(const enum intel_engine_hangcheck_action a)
switch (a) {
return "idle";
return "wait";
return "active seqno";
return "active head";
return "active subunits";
return "wait kick";
return "dead";
return "unknown";
#define I915_MAX_SLICES 3
#define I915_MAX_SUBSLICES 3
#define instdone_slice_mask(dev_priv__) \
(INTEL_GEN(dev_priv__) == 7 ? \
1 : INTEL_INFO(dev_priv__)->sseu.slice_mask)
#define instdone_subslice_mask(dev_priv__) \
(INTEL_GEN(dev_priv__) == 7 ? \
1 : INTEL_INFO(dev_priv__)->sseu.subslice_mask)
#define for_each_instdone_slice_subslice(dev_priv__, slice__, subslice__) \
for ((slice__) = 0, (subslice__) = 0; \
(slice__) < I915_MAX_SLICES; \
(subslice__) = ((subslice__) + 1) < I915_MAX_SUBSLICES ? (subslice__) + 1 : 0, \
(slice__) += ((subslice__) == 0)) \
for_each_if((BIT(slice__) & instdone_slice_mask(dev_priv__)) && \
(BIT(subslice__) & instdone_subslice_mask(dev_priv__)))
struct intel_instdone {
u32 instdone;
/* The following exist only in the RCS engine */
u32 slice_common;
u32 sampler[I915_MAX_SLICES][I915_MAX_SUBSLICES];
struct intel_engine_hangcheck {
u64 acthd;
u32 seqno;
enum intel_engine_hangcheck_action action;
unsigned long action_timestamp;
int deadlock;
struct intel_instdone instdone;
struct drm_i915_gem_request *active_request;
bool stalled;
struct intel_ring {
struct i915_vma *vma;
void *vaddr;
struct list_head request_list;
u32 head;
u32 tail;
u32 emit;
u32 space;
u32 size;
u32 effective_size;
struct i915_gem_context;
struct drm_i915_reg_table;
* we use a single page to load ctx workarounds so all of these
* values are referred in terms of dwords
* struct i915_wa_ctx_bb:
* offset: specifies batch starting position, also helpful in case
* if we want to have multiple batches at different offsets based on
* some criteria. It is not a requirement at the moment but provides
* an option for future use.
* size: size of the batch in DWORDS
struct i915_ctx_workarounds {
struct i915_wa_ctx_bb {
u32 offset;
u32 size;
} indirect_ctx, per_ctx;
struct i915_vma *vma;
struct drm_i915_gem_request;
struct intel_render_state;
* Engine IDs definitions.
* Keep instances of the same type engine together.
enum intel_engine_id {
RCS = 0,
#define _VCS(n) (VCS + (n))
struct i915_priolist {
struct rb_node node;
struct list_head requests;
int priority;
struct intel_engine_cs {
struct drm_i915_private *i915;
enum intel_engine_id id;
unsigned int uabi_id;
unsigned int hw_id;
unsigned int guc_id;
u8 class;
u8 instance;
u32 context_size;
u32 mmio_base;
unsigned int irq_shift;
struct intel_ring *buffer;
struct intel_timeline *timeline;
struct intel_render_state *render_state;
atomic_t irq_count;
unsigned long irq_posted;
/* Rather than have every client wait upon all user interrupts,
* with the herd waking after every interrupt and each doing the
* heavyweight seqno dance, we delegate the task (of being the
* bottom-half of the user interrupt) to the first client. After
* every interrupt, we wake up one client, who does the heavyweight
* coherent seqno read and either goes back to sleep (if incomplete),
* or wakes up all the completed clients in parallel, before then
* transferring the bottom-half status to the next client in the queue.
* Compared to walking the entire list of waiters in a single dedicated
* bottom-half, we reduce the latency of the first waiter by avoiding
* a context switch, but incur additional coherent seqno reads when
* following the chain of request breadcrumbs. Since it is most likely
* that we have a single client waiting on each seqno, then reducing
* the overhead of waking that client is much preferred.
struct intel_breadcrumbs {
spinlock_t irq_lock; /* protects irq_*; irqsafe */
struct intel_wait *irq_wait; /* oldest waiter by retirement */
spinlock_t rb_lock; /* protects the rb and wraps irq_lock */
struct rb_root waiters; /* sorted by retirement, priority */
struct rb_root signals; /* sorted by retirement */
struct task_struct *signaler; /* used for fence signalling */
struct drm_i915_gem_request __rcu *first_signal;
struct timer_list fake_irq; /* used after a missed interrupt */
struct timer_list hangcheck; /* detect missed interrupts */
unsigned int hangcheck_interrupts;
bool irq_armed : 1;
bool irq_enabled : 1;
I915_SELFTEST_DECLARE(bool mock : 1);
} breadcrumbs;
* A pool of objects to use as shadow copies of client batch buffers
* when the command parser is enabled. Prevents the client from
* modifying the batch contents after software parsing.
struct i915_gem_batch_pool batch_pool;
struct intel_hw_status_page status_page;
struct i915_ctx_workarounds wa_ctx;
struct i915_vma *scratch;
u32 irq_keep_mask; /* always keep these interrupts */
u32 irq_enable_mask; /* bitmask to enable ring interrupt */
void (*irq_enable)(struct intel_engine_cs *engine);
void (*irq_disable)(struct intel_engine_cs *engine);
int (*init_hw)(struct intel_engine_cs *engine);
void (*reset_hw)(struct intel_engine_cs *engine,
struct drm_i915_gem_request *req);
void (*set_default_submission)(struct intel_engine_cs *engine);
struct intel_ring *(*context_pin)(struct intel_engine_cs *engine,
struct i915_gem_context *ctx);
void (*context_unpin)(struct intel_engine_cs *engine,
struct i915_gem_context *ctx);
int (*request_alloc)(struct drm_i915_gem_request *req);
int (*init_context)(struct drm_i915_gem_request *req);
int (*emit_flush)(struct drm_i915_gem_request *request,
u32 mode);
#define EMIT_FLUSH BIT(1)
int (*emit_bb_start)(struct drm_i915_gem_request *req,
u64 offset, u32 length,
unsigned int dispatch_flags);
#define I915_DISPATCH_RS BIT(2)
void (*emit_breadcrumb)(struct drm_i915_gem_request *req,
u32 *cs);
int emit_breadcrumb_sz;
/* Pass the request to the hardware queue (e.g. directly into
* the legacy ringbuffer or to the end of an execlist).
* This is called from an atomic context with irqs disabled; must
* be irq safe.
void (*submit_request)(struct drm_i915_gem_request *req);
/* Call when the priority on a request has changed and it and its
* dependencies may need rescheduling. Note the request itself may
* not be ready to run!
* Called under the struct_mutex.
void (*schedule)(struct drm_i915_gem_request *request,
int priority);
/* Some chipsets are not quite as coherent as advertised and need
* an expensive kick to force a true read of the up-to-date seqno.
* However, the up-to-date seqno is not always required and the last
* seen value is good enough. Note that the seqno will always be
* monotonic, even if not coherent.
void (*irq_seqno_barrier)(struct intel_engine_cs *engine);
void (*cleanup)(struct intel_engine_cs *engine);
/* GEN8 signal/wait table - never trust comments!
* signal to signal to signal to signal to signal to
* --------------------------------------------------------------------
* RCS | NOP (0x00) | VCS (0x08) | BCS (0x10) | VECS (0x18) | VCS2 (0x20) |
* |-------------------------------------------------------------------
* VCS | RCS (0x28) | NOP (0x30) | BCS (0x38) | VECS (0x40) | VCS2 (0x48) |
* |-------------------------------------------------------------------
* BCS | RCS (0x50) | VCS (0x58) | NOP (0x60) | VECS (0x68) | VCS2 (0x70) |
* |-------------------------------------------------------------------
* VECS | RCS (0x78) | VCS (0x80) | BCS (0x88) | NOP (0x90) | VCS2 (0x98) |
* |-------------------------------------------------------------------
* VCS2 | RCS (0xa0) | VCS (0xa8) | BCS (0xb0) | VECS (0xb8) | NOP (0xc0) |
* |-------------------------------------------------------------------
* Generalization:
* f(x, y) := (x->id * NUM_RINGS * seqno_size) + (seqno_size * y->id)
* ie. transpose of g(x, y)
* sync from sync from sync from sync from sync from
* --------------------------------------------------------------------
* RCS | NOP (0x00) | VCS (0x28) | BCS (0x50) | VECS (0x78) | VCS2 (0xa0) |
* |-------------------------------------------------------------------
* VCS | RCS (0x08) | NOP (0x30) | BCS (0x58) | VECS (0x80) | VCS2 (0xa8) |
* |-------------------------------------------------------------------
* BCS | RCS (0x10) | VCS (0x38) | NOP (0x60) | VECS (0x88) | VCS2 (0xb0) |
* |-------------------------------------------------------------------
* VECS | RCS (0x18) | VCS (0x40) | BCS (0x68) | NOP (0x90) | VCS2 (0xb8) |
* |-------------------------------------------------------------------
* VCS2 | RCS (0x20) | VCS (0x48) | BCS (0x70) | VECS (0x98) | NOP (0xc0) |
* |-------------------------------------------------------------------
* Generalization:
* g(x, y) := (y->id * NUM_RINGS * seqno_size) + (seqno_size * x->id)
* ie. transpose of f(x, y)
struct {
union {
struct {
/* our mbox written by others */
/* mboxes this ring signals to */
i915_reg_t signal[GEN6_NUM_SEMAPHORES];
} mbox;
u64 signal_ggtt[I915_NUM_ENGINES];
/* AKA wait() */
int (*sync_to)(struct drm_i915_gem_request *req,
struct drm_i915_gem_request *signal);
u32 *(*signal)(struct drm_i915_gem_request *req, u32 *cs);
} semaphore;
/* Execlists */
struct tasklet_struct irq_tasklet;
struct i915_priolist default_priolist;
bool no_priolist;
struct execlist_port {
struct drm_i915_gem_request *request_count;
#define port_request(p) ptr_mask_bits((p)->request_count, EXECLIST_COUNT_BITS)
#define port_count(p) ptr_unmask_bits((p)->request_count, EXECLIST_COUNT_BITS)
#define port_pack(rq, count) ptr_pack_bits(rq, count, EXECLIST_COUNT_BITS)
#define port_unpack(p, count) ptr_unpack_bits((p)->request_count, count, EXECLIST_COUNT_BITS)
#define port_set(p, packed) ((p)->request_count = (packed))
#define port_isset(p) ((p)->request_count)
#define port_index(p, e) ((p) - (e)->execlist_port)
GEM_DEBUG_DECL(u32 context_id);
} execlist_port[2];
struct rb_root execlist_queue;
struct rb_node *execlist_first;
unsigned int fw_domains;
/* Contexts are pinned whilst they are active on the GPU. The last
* context executed remains active whilst the GPU is idle - the
* switch away and write to the context object only occurs on the
* next execution. Contexts are only unpinned on retirement of the
* following request ensuring that we can always write to the object
* on the context switch even after idling. Across suspend, we switch
* to the kernel context and trash it as the save may not happen
* before the hardware is powered down.
struct i915_gem_context *last_retired_context;
/* We track the current MI_SET_CONTEXT in order to eliminate
* redudant context switches. This presumes that requests are not
* reordered! Or when they are the tracking is updated along with
* the emission of individual requests into the legacy command
* stream (ring).
struct i915_gem_context *legacy_active_context;
/* status_notifier: list of callbacks for context-switch changes */
struct atomic_notifier_head context_status_notifier;
struct intel_engine_hangcheck hangcheck;
bool needs_cmd_parser;
* Table of commands the command parser needs to know about
* for this engine.
* Table of registers allowed in commands that read/write registers.
const struct drm_i915_reg_table *reg_tables;
int reg_table_count;
* Returns the bitmask for the length field of the specified command.
* Return 0 for an unrecognized/invalid command.
* If the command parser finds an entry for a command in the engine's
* cmd_tables, it gets the command's length based on the table entry.
* If not, it calls this function to determine the per-engine length
* field encoding for the command (i.e. different opcode ranges use
* certain bits to encode the command length in the header).
u32 (*get_cmd_length_mask)(u32 cmd_header);
static inline unsigned int
intel_engine_flag(const struct intel_engine_cs *engine)
return BIT(engine->id);
static inline u32
intel_read_status_page(struct intel_engine_cs *engine, int reg)
/* Ensure that the compiler doesn't optimize away the load. */
return READ_ONCE(engine->status_page.page_addr[reg]);
static inline void
intel_write_status_page(struct intel_engine_cs *engine, int reg, u32 value)
/* Writing into the status page should be done sparingly. Since
* we do when we are uncertain of the device state, we take a bit
* of extra paranoia to try and ensure that the HWS takes the value
* we give and that it doesn't end up trapped inside the CPU!
if (static_cpu_has(X86_FEATURE_CLFLUSH)) {
engine->status_page.page_addr[reg] = value;
} else {
WRITE_ONCE(engine->status_page.page_addr[reg], value);
* Reads a dword out of the status page, which is written to from the command
* queue by automatic updates, MI_REPORT_HEAD, MI_STORE_DATA_INDEX, or
* The following dwords have a reserved meaning:
* 0x00: ISR copy, updated when an ISR bit not set in the HWSTAM changes.
* 0x04: ring 0 head pointer
* 0x05: ring 1 head pointer (915-class)
* 0x06: ring 2 head pointer (915-class)
* 0x10-0x1b: Context status DWords (GM45)
* 0x1f: Last written status offset. (GM45)
* 0x20-0x2f: Reserved (Gen6+)
* The area from dword 0x30 to 0x3ff is available for driver usage.
#define I915_GEM_HWS_INDEX 0x30
#define I915_GEM_HWS_SCRATCH_INDEX 0x40
struct intel_ring *
intel_engine_create_ring(struct intel_engine_cs *engine, int size);
int intel_ring_pin(struct intel_ring *ring,
struct drm_i915_private *i915,
unsigned int offset_bias);
void intel_ring_reset(struct intel_ring *ring, u32 tail);
unsigned int intel_ring_update_space(struct intel_ring *ring);
void intel_ring_unpin(struct intel_ring *ring);
void intel_ring_free(struct intel_ring *ring);
void intel_engine_stop(struct intel_engine_cs *engine);
void intel_engine_cleanup(struct intel_engine_cs *engine);
void intel_legacy_submission_resume(struct drm_i915_private *dev_priv);
int __must_check intel_ring_cacheline_align(struct drm_i915_gem_request *req);
u32 __must_check *intel_ring_begin(struct drm_i915_gem_request *req,
unsigned int n);
static inline void
intel_ring_advance(struct drm_i915_gem_request *req, u32 *cs)
/* Dummy function.
* This serves as a placeholder in the code so that the reader
* can compare against the preceding intel_ring_begin() and
* check that the number of dwords emitted matches the space
* reserved for the command packet (i.e. the value passed to
* intel_ring_begin()).
GEM_BUG_ON((req->ring->vaddr + req->ring->emit) != cs);
static inline u32
intel_ring_wrap(const struct intel_ring *ring, u32 pos)
return pos & (ring->size - 1);
static inline u32
intel_ring_offset(const struct drm_i915_gem_request *req, void *addr)
/* Don't write ring->size (equivalent to 0) as that hangs some GPUs. */
u32 offset = addr - req->ring->vaddr;
GEM_BUG_ON(offset > req->ring->size);
return intel_ring_wrap(req->ring, offset);
static inline void
assert_ring_tail_valid(const struct intel_ring *ring, unsigned int tail)
/* We could combine these into a single tail operation, but keeping
* them as seperate tests will help identify the cause should one
* ever fire.
GEM_BUG_ON(tail >= ring->size);
* "Ring Buffer Use"
* Gen2 BSpec "1. Programming Environment" /
* Gen3 BSpec "1c Memory Interface Functions" /
* Gen4+ BSpec "1c Memory Interface and Command Stream" /
* "If the Ring Buffer Head Pointer and the Tail Pointer are on the
* same cacheline, the Head Pointer must not be greater than the Tail
* Pointer."
* We use ring->head as the last known location of the actual RING_HEAD,
* it may have advanced but in the worst case it is equally the same
* as ring->head and so we should never program RING_TAIL to advance
* into the same cacheline as ring->head.
#define cacheline(a) round_down(a, CACHELINE_BYTES)
GEM_BUG_ON(cacheline(tail) == cacheline(ring->head) &&
tail < ring->head);
#undef cacheline
static inline unsigned int
intel_ring_set_tail(struct intel_ring *ring, unsigned int tail)
/* Whilst writes to the tail are strictly order, there is no
* serialisation between readers and the writers. The tail may be
* read by i915_gem_request_retire() just as it is being updated
* by execlists, as although the breadcrumb is complete, the context
* switch hasn't been seen.
assert_ring_tail_valid(ring, tail);
ring->tail = tail;
return tail;
void intel_engine_init_global_seqno(struct intel_engine_cs *engine, u32 seqno);
void intel_engine_setup_common(struct intel_engine_cs *engine);
int intel_engine_init_common(struct intel_engine_cs *engine);
int intel_engine_create_scratch(struct intel_engine_cs *engine, int size);
void intel_engine_cleanup_common(struct intel_engine_cs *engine);
int intel_init_render_ring_buffer(struct intel_engine_cs *engine);
int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine);
int intel_init_blt_ring_buffer(struct intel_engine_cs *engine);
int intel_init_vebox_ring_buffer(struct intel_engine_cs *engine);
u64 intel_engine_get_active_head(struct intel_engine_cs *engine);
u64 intel_engine_get_last_batch_head(struct intel_engine_cs *engine);
static inline u32 intel_engine_get_seqno(struct intel_engine_cs *engine)
return intel_read_status_page(engine, I915_GEM_HWS_INDEX);
static inline u32 intel_engine_last_submit(struct intel_engine_cs *engine)
/* We are only peeking at the tail of the submit queue (and not the
* queue itself) in order to gain a hint as to the current active
* state of the engine. Callers are not expected to be taking
* engine->timeline->lock, nor are they expected to be concerned
* wtih serialising this hint with anything, so document it as
* a hint and nothing more.
return READ_ONCE(engine->timeline->seqno);
int init_workarounds_ring(struct intel_engine_cs *engine);
int intel_ring_workarounds_emit(struct drm_i915_gem_request *req);
void intel_engine_get_instdone(struct intel_engine_cs *engine,
struct intel_instdone *instdone);
* Arbitrary size for largest possible 'add request' sequence. The code paths
* are complex and variable. Empirical measurement shows that the worst case
* is BDW at 192 bytes (6 + 6 + 36 dwords), then ILK at 136 bytes. However,
* we need to allocate double the largest single packet within that emission
* to account for tail wraparound (so 6 + 6 + 72 dwords for BDW).
static inline u32 intel_hws_seqno_address(struct intel_engine_cs *engine)
return engine->status_page.ggtt_offset + I915_GEM_HWS_INDEX_ADDR;
/* intel_breadcrumbs.c -- user interrupt bottom-half for waiters */
int intel_engine_init_breadcrumbs(struct intel_engine_cs *engine);
static inline void intel_wait_init(struct intel_wait *wait,
struct drm_i915_gem_request *rq)
wait->tsk = current;
wait->request = rq;
static inline void intel_wait_init_for_seqno(struct intel_wait *wait, u32 seqno)
wait->tsk = current;
wait->seqno = seqno;
static inline bool intel_wait_has_seqno(const struct intel_wait *wait)
return wait->seqno;
static inline bool
intel_wait_update_seqno(struct intel_wait *wait, u32 seqno)
wait->seqno = seqno;
return intel_wait_has_seqno(wait);
static inline bool
intel_wait_update_request(struct intel_wait *wait,
const struct drm_i915_gem_request *rq)
return intel_wait_update_seqno(wait, i915_gem_request_global_seqno(rq));
static inline bool
intel_wait_check_seqno(const struct intel_wait *wait, u32 seqno)
return wait->seqno == seqno;
static inline bool
intel_wait_check_request(const struct intel_wait *wait,
const struct drm_i915_gem_request *rq)
return intel_wait_check_seqno(wait, i915_gem_request_global_seqno(rq));
static inline bool intel_wait_complete(const struct intel_wait *wait)
return RB_EMPTY_NODE(&wait->node);
bool intel_engine_add_wait(struct intel_engine_cs *engine,
struct intel_wait *wait);
void intel_engine_remove_wait(struct intel_engine_cs *engine,
struct intel_wait *wait);
void intel_engine_enable_signaling(struct drm_i915_gem_request *request,
bool wakeup);
void intel_engine_cancel_signaling(struct drm_i915_gem_request *request);
static inline bool intel_engine_has_waiter(const struct intel_engine_cs *engine)
return READ_ONCE(engine->breadcrumbs.irq_wait);
unsigned int intel_engine_wakeup(struct intel_engine_cs *engine);
void __intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine);
void intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine);
void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine);
void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
bool intel_breadcrumbs_busy(struct intel_engine_cs *engine);
static inline u32 *gen8_emit_pipe_control(u32 *batch, u32 flags, u32 offset)
memset(batch, 0, 6 * sizeof(u32));
batch[0] = GFX_OP_PIPE_CONTROL(6);
batch[1] = flags;
batch[2] = offset;
return batch + 6;
bool intel_engine_is_idle(struct intel_engine_cs *engine);
bool intel_engines_are_idle(struct drm_i915_private *dev_priv);
void intel_engines_mark_idle(struct drm_i915_private *i915);
void intel_engines_reset_default_submission(struct drm_i915_private *i915);
static inline bool
__intel_engine_can_store_dword(unsigned int gen, unsigned int class)
if (gen <= 2)
return false; /* uses physical not virtual addresses */
if (gen == 6 && class == VIDEO_DECODE_CLASS)
return false; /* b0rked */
return true;
#endif /* _INTEL_RINGBUFFER_H_ */