Since we have a sequence of register reads and writes, we can reduce the latency of starting the BSD ring by performing all the mmio operations under the same forcewake wakeref.
Signed-off-by: Chris Wilson <[email protected]> Reviewed-by: Tvrtko Ursulin <[email protected]> --- drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/intel_ringbuffer.c | 28 ++++++++++++++++------------ 2 files changed, 17 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 48d30676455e..485ab1148181 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -3882,6 +3882,7 @@ __raw_write(64, q) */ #define I915_READ_FW(reg__) __raw_i915_read32(dev_priv, (reg__)) #define I915_WRITE_FW(reg__, val__) __raw_i915_write32(dev_priv, (reg__), (val__)) +#define I915_WRITE64_FW(reg__, val__) __raw_i915_write64(dev_priv, (reg__), (val__)) #define POSTING_READ_FW(reg__) (void)I915_READ_FW(reg__) /* "Broadcast RGB" property */ diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index c4365cc1f133..7c93d4c210e5 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -2684,34 +2684,38 @@ static void gen6_bsd_ring_write_tail(struct intel_engine_cs *engine, { struct drm_i915_private *dev_priv = engine->i915; + intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL); + /* Every tail move must follow the sequence below */ /* Disable notification that the ring is IDLE. The GT * will then assume that it is busy and bring it out of rc6. */ - I915_WRITE(GEN6_BSD_SLEEP_PSMI_CONTROL, - _MASKED_BIT_ENABLE(GEN6_BSD_SLEEP_MSG_DISABLE)); + I915_WRITE_FW(GEN6_BSD_SLEEP_PSMI_CONTROL, + _MASKED_BIT_ENABLE(GEN6_BSD_SLEEP_MSG_DISABLE)); /* Clear the context id. Here be magic! */ - I915_WRITE64(GEN6_BSD_RNCID, 0x0); + I915_WRITE64_FW(GEN6_BSD_RNCID, 0x0); /* Wait for the ring not to be idle, i.e. for it to wake up. */ - if (intel_wait_for_register(dev_priv, - GEN6_BSD_SLEEP_PSMI_CONTROL, - GEN6_BSD_SLEEP_INDICATOR, - 0, - 50)) + if (intel_wait_for_register_fw(dev_priv, + GEN6_BSD_SLEEP_PSMI_CONTROL, + GEN6_BSD_SLEEP_INDICATOR, + 0, + 50)) DRM_ERROR("timed out waiting for the BSD ring to wake up\n"); /* Now that the ring is fully powered up, update the tail */ - I915_WRITE_TAIL(engine, value); - POSTING_READ(RING_TAIL(engine->mmio_base)); + I915_WRITE_FW(RING_TAIL(engine->mmio_base), value); + POSTING_READ_FW(RING_TAIL(engine->mmio_base)); /* Let the ring send IDLE messages to the GT again, * and so let it sleep to conserve power when idle. */ - I915_WRITE(GEN6_BSD_SLEEP_PSMI_CONTROL, - _MASKED_BIT_DISABLE(GEN6_BSD_SLEEP_MSG_DISABLE)); + I915_WRITE_FW(GEN6_BSD_SLEEP_PSMI_CONTROL, + _MASKED_BIT_DISABLE(GEN6_BSD_SLEEP_MSG_DISABLE)); + + intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL); } static int gen6_bsd_ring_flush(struct drm_i915_gem_request *req, -- 2.8.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
