On 05/01/2019 02:39, Carlos Santa wrote:
From: Michel Thierry <michel.thie...@intel.com>
Emit the required commands into the ring buffer for starting and
stopping the watchdog timer before/after batch buffer start during
batch buffer submission.
v2: Support watchdog threshold per context engine, merge lri commands,
and move watchdog commands emission to emit_bb_start. Request space of
combined start_watchdog, bb_start and stop_watchdog to avoid any error
after emitting bb_start.
v3: There were too many req->engine in emit_bb_start.
Use GEM_BUG_ON instead of returning a very late EINVAL in the remote
case of watchdog misprogramming; set correct LRI cmd size in
emit_stop_watchdog. (Chris)
v4: Rebase.
v5: use to_intel_context instead of ctx->engine.
v6: Rebase.
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Antonio Argenziano <antonio.argenzi...@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursu...@linux.intel.com>
Signed-off-by: Michel Thierry <michel.thie...@intel.com>
Signed-off-by: Carlos Santa <carlos.sa...@intel.com>
---
drivers/gpu/drm/i915/i915_gem_context.h | 4 ++
drivers/gpu/drm/i915/intel_lrc.c | 80 ++++++++++++++++++++++++-
drivers/gpu/drm/i915/intel_ringbuffer.h | 4 ++
3 files changed, 86 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h
b/drivers/gpu/drm/i915/i915_gem_context.h
index f6d870b1f73e..62f4eb04985b 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -169,6 +169,10 @@ struct i915_gem_context {
u32 *lrc_reg_state;
u64 lrc_desc;
int pin_count;
+ /** watchdog_threshold: hw watchdog threshold value,
+ * in clock counts
+ */
+ u32 watchdog_threshold;
const struct intel_context_ops *ops;
} __engine[I915_NUM_ENGINES];
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index e1dcdf545bee..0ea5a37c3357 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1872,12 +1872,33 @@ static int gen8_emit_bb_start(struct i915_request *rq,
u64 offset, u32 len,
const unsigned int flags)
{
+ struct intel_engine_cs *engine = rq->engine;
u32 *cs;
+ u32 num_dwords;
+ bool watchdog_running = false;
Hm it's not really running but should be running, but ok. I'd just find
something lie 'run_watchdog' or 'enable_watchdog' clearer.
- cs = intel_ring_begin(rq, 6);
+ /* bb_start only */
+ num_dwords = 6;
+
+ /* check if watchdog will be required */
+ if (to_intel_context(rq->gem_context, engine)->watchdog_threshold != 0)
{
+ GEM_BUG_ON(!engine->emit_start_watchdog ||
+ !engine->emit_stop_watchdog);
+
+ /* + start_watchdog (6) + stop_watchdog (4) */
+ num_dwords += 10;
+ watchdog_running = true;
+ }
+
+ cs = intel_ring_begin(rq, num_dwords);
if (IS_ERR(cs))
return PTR_ERR(cs);
+ if (watchdog_running) {
+ /* Start watchdog timer */
+ cs = engine->emit_start_watchdog(rq, cs);
+ }
+
/*
* WaDisableCtxRestoreArbitration:bdw,chv
*
@@ -1906,8 +1927,12 @@ static int gen8_emit_bb_start(struct i915_request *rq,
*cs++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
*cs++ = MI_NOOP;
It could be neater to avoid to many MI_NOOPs. I think if you'd make emit
start/stop not emit it, and moved this line above to be last, a single
MI_MOOP could be emitted conditionally if the total number of emitted
(based on cs pointer) is odd.
- intel_ring_advance(rq, cs);
+ if (watchdog_running) {
+ /* Cancel watchdog timer */
+ cs = engine->emit_stop_watchdog(rq, cs);
+ }
+ intel_ring_advance(rq, cs);
return 0;
}
@@ -2091,6 +2116,49 @@ static void gen8_watchdog_irq_handler(unsigned long data)
intel_uncore_forcewake_put(dev_priv, fw_domains);
}
+static u32 *gen8_emit_start_watchdog(struct i915_request *rq, u32 *cs)
+{
+ struct intel_engine_cs *engine = rq->engine;
+ struct i915_gem_context *ctx = rq->gem_context;
+ struct intel_context *ce = to_intel_context(ctx, engine);
+
+ /* XXX: no watchdog support in BCS engine */
+ GEM_BUG_ON(engine->id == BCS);
+
+ /*
+ * watchdog register must never be programmed to zero. This would
+ * cause the watchdog counter to exceed and not allow the engine to
Waht does exceed mean here?
+ * go into IDLE state
+ */
+ GEM_BUG_ON(ce->watchdog_threshold == 0);
+
+ /* Set counter period */
+ *cs++ = MI_LOAD_REGISTER_IMM(2);
+ *cs++ = i915_mmio_reg_offset(RING_THRESH(engine->mmio_base));
+ *cs++ = ce->watchdog_threshold;
+ /* Start counter */
+ *cs++ = i915_mmio_reg_offset(RING_CNTR(engine->mmio_base));
+ *cs++ = GEN8_WATCHDOG_ENABLE;
+ *cs++ = MI_NOOP;
+
+ return cs;
+}
+
+static u32 *gen8_emit_stop_watchdog(struct i915_request *rq, u32 *cs)
+{
+ struct intel_engine_cs *engine = rq->engine;
+
+ /* XXX: no watchdog support in BCS engine */
+ GEM_BUG_ON(engine->id == BCS);
I think there will be enough of these checks (including the previous
patch) to warrant engine->flags |= I915_ENGINE_SUPPORTS_WATCHDOG.
+
+ *cs++ = MI_LOAD_REGISTER_IMM(1);
+ *cs++ = i915_mmio_reg_offset(RING_CNTR(engine->mmio_base));
+ *cs++ = get_watchdog_disable(engine);
Since this helper now potentially runs on every bb end perhaps it is
worth storing the magic value in the engine instead of running the
conditionals every time.
+ *cs++ = MI_NOOP;
+
+ return cs;
+}
+
/*
* Reserve space for 2 NOOPs at the end of each request to be
* used as a workaround for not being allowed to do lite
@@ -2366,6 +2434,8 @@ int logical_render_ring_init(struct intel_engine_cs
*engine)
engine->emit_flush = gen8_emit_flush_render;
engine->emit_breadcrumb = gen8_emit_breadcrumb_rcs;
engine->emit_breadcrumb_sz = gen8_emit_breadcrumb_rcs_sz;
+ engine->emit_start_watchdog = gen8_emit_start_watchdog;
+ engine->emit_stop_watchdog = gen8_emit_stop_watchdog;
I don't see that these two need to be vfuncs - am I missing something?
ret = logical_ring_init(engine);
if (ret)
@@ -2392,6 +2462,12 @@ int logical_xcs_ring_init(struct intel_engine_cs *engine)
{
logical_ring_setup(engine);
+ /* BCS engine does not have a watchdog-expired irq */
+ if (engine->id != BCS) {
+ engine->emit_start_watchdog = gen8_emit_start_watchdog;
+ engine->emit_stop_watchdog = gen8_emit_stop_watchdog;
+ }
+
return logical_ring_init(engine);
}
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 6cb8b4280035..c7aa842a2db1 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -469,6 +469,10 @@ struct intel_engine_cs {
int (*init_context)(struct i915_request *rq);
int (*emit_flush)(struct i915_request *request, u32 mode);
+ u32 * (*emit_start_watchdog)(struct i915_request *rq,
+ u32 *cs);
+ u32 * (*emit_stop_watchdog)(struct i915_request *rq,
+ u32 *cs);
#define EMIT_INVALIDATE BIT(0)
#define EMIT_FLUSH BIT(1)
#define EMIT_BARRIER (EMIT_INVALIDATE | EMIT_FLUSH)
Regards,
Tvrtko
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