[Intel-gfx] [PATCH 4/8] drm/i915: Make all GPU resets atomic

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> In preparation for the next few commits, make resetting the GPU atomic.
> Currently, we have prepared gen6+ for atomic resetting of individual
> engines, but now there is a requirement to perform the whole device
> level reset (just the register poking) from inside an atomic context.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_reset.c             | 50 ++++++++++---------
>  .../gpu/drm/i915/selftests/mock_gem_device.c  |  4 +-
>  2 files changed, 29 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c
> index e2e40b44a9a8..f9512e07646d 100644
> --- a/drivers/gpu/drm/i915/i915_reset.c
> +++ b/drivers/gpu/drm/i915/i915_reset.c
> @@ -144,14 +144,14 @@ static int i915_do_reset(struct drm_i915_private *i915,
>  
>  	/* Assert reset for at least 20 usec, and wait for acknowledgement. */
>  	pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
> -	usleep_range(50, 200);
> -	err = wait_for(i915_in_reset(pdev), 500);
> +	udelay(50);
> +	err = wait_for_atomic(i915_in_reset(pdev), 50);
>  
>  	/* Clear the reset request. */
>  	pci_write_config_byte(pdev, I915_GDRST, 0);
> -	usleep_range(50, 200);
> +	udelay(50);
>  	if (!err)
> -		err = wait_for(!i915_in_reset(pdev), 500);
> +		err = wait_for_atomic(!i915_in_reset(pdev), 50);

50ms still seems long but I guess you want to play it safe.

Wouldn't it be nice if we would get easily publish a completion
time value to some external database from CI.

>  
>  	return err;
>  }
> @@ -171,7 +171,7 @@ static int g33_do_reset(struct drm_i915_private *i915,
>  	struct pci_dev *pdev = i915->drm.pdev;
>  
>  	pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
> -	return wait_for(g4x_reset_complete(pdev), 500);
> +	return wait_for_atomic(g4x_reset_complete(pdev), 50);
>  }
>  
>  static int g4x_do_reset(struct drm_i915_private *dev_priv,
> @@ -182,13 +182,13 @@ static int g4x_do_reset(struct drm_i915_private *dev_priv,
>  	int ret;
>  
>  	/* WaVcpClkGateDisableForMediaReset:ctg,elk */
> -	I915_WRITE(VDECCLK_GATE_D,
> -		   I915_READ(VDECCLK_GATE_D) | VCP_UNIT_CLOCK_GATE_DISABLE);
> -	POSTING_READ(VDECCLK_GATE_D);
> +	I915_WRITE_FW(VDECCLK_GATE_D,
> +		      I915_READ(VDECCLK_GATE_D) | VCP_UNIT_CLOCK_GATE_DISABLE);
> +	POSTING_READ_FW(VDECCLK_GATE_D);
>  
>  	pci_write_config_byte(pdev, I915_GDRST,
>  			      GRDOM_MEDIA | GRDOM_RESET_ENABLE);
> -	ret =  wait_for(g4x_reset_complete(pdev), 500);
> +	ret =  wait_for_atomic(g4x_reset_complete(pdev), 50);
>  	if (ret) {
>  		DRM_DEBUG_DRIVER("Wait for media reset failed\n");
>  		goto out;
> @@ -196,7 +196,7 @@ static int g4x_do_reset(struct drm_i915_private *dev_priv,
>  
>  	pci_write_config_byte(pdev, I915_GDRST,
>  			      GRDOM_RENDER | GRDOM_RESET_ENABLE);
> -	ret =  wait_for(g4x_reset_complete(pdev), 500);
> +	ret =  wait_for_atomic(g4x_reset_complete(pdev), 50);
>  	if (ret) {
>  		DRM_DEBUG_DRIVER("Wait for render reset failed\n");
>  		goto out;
> @@ -205,9 +205,9 @@ static int g4x_do_reset(struct drm_i915_private *dev_priv,
>  out:
>  	pci_write_config_byte(pdev, I915_GDRST, 0);
>  
> -	I915_WRITE(VDECCLK_GATE_D,
> -		   I915_READ(VDECCLK_GATE_D) & ~VCP_UNIT_CLOCK_GATE_DISABLE);
> -	POSTING_READ(VDECCLK_GATE_D);
> +	I915_WRITE_FW(VDECCLK_GATE_D,
> +		      I915_READ(VDECCLK_GATE_D) & ~VCP_UNIT_CLOCK_GATE_DISABLE);
> +	POSTING_READ_FW(VDECCLK_GATE_D);
>  
>  	return ret;
>  }
> @@ -218,27 +218,29 @@ static int ironlake_do_reset(struct drm_i915_private *dev_priv,
>  {
>  	int ret;
>  
> -	I915_WRITE(ILK_GDSR, ILK_GRDOM_RENDER | ILK_GRDOM_RESET_ENABLE);
> -	ret = intel_wait_for_register(dev_priv,
> -				      ILK_GDSR, ILK_GRDOM_RESET_ENABLE, 0,
> -				      500);
> +	I915_WRITE_FW(ILK_GDSR, ILK_GRDOM_RENDER | ILK_GRDOM_RESET_ENABLE);
> +	ret = __intel_wait_for_register_fw(dev_priv, ILK_GDSR,
> +					   ILK_GRDOM_RESET_ENABLE, 0,
> +					   5000, 0,
> +					   NULL);

>From 500ms to 5ms. There has been some slack in there for sure...

>  	if (ret) {
>  		DRM_DEBUG_DRIVER("Wait for render reset failed\n");
>  		goto out;
>  	}
>  
> -	I915_WRITE(ILK_GDSR, ILK_GRDOM_MEDIA | ILK_GRDOM_RESET_ENABLE);
> -	ret = intel_wait_for_register(dev_priv,
> -				      ILK_GDSR, ILK_GRDOM_RESET_ENABLE, 0,
> -				      500);
> +	I915_WRITE_FW(ILK_GDSR, ILK_GRDOM_MEDIA | ILK_GRDOM_RESET_ENABLE);
> +	ret = __intel_wait_for_register_fw(dev_priv, ILK_GDSR,
> +					   ILK_GRDOM_RESET_ENABLE, 0,
> +					   5000, 0,
> +					   NULL);
>  	if (ret) {
>  		DRM_DEBUG_DRIVER("Wait for media reset failed\n");
>  		goto out;
>  	}
>  
>  out:
> -	I915_WRITE(ILK_GDSR, 0);
> -	POSTING_READ(ILK_GDSR);
> +	I915_WRITE_FW(ILK_GDSR, 0);
> +	POSTING_READ_FW(ILK_GDSR);
>  	return ret;
>  }
>  
> @@ -572,7 +574,9 @@ int intel_gpu_reset(struct drm_i915_private *i915, unsigned int engine_mask)
>  		ret = -ENODEV;
>  		if (reset) {

Ok, i might have missed some spot but for me it looks
like you can lift the might_sleep_if(engine_mask == ALL_ENGINES)
from above.

>  			GEM_TRACE("engine_mask=%x\n", engine_mask);
> +			preempt_disable();
>  			ret = reset(i915, engine_mask, retry);
> +			preempt_enable();
>  		}
>  		if (ret != -ETIMEDOUT || engine_mask != ALL_ENGINES)
>  			break;
> diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> index 3cda66292e76..888c6978bc54 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> @@ -58,8 +58,8 @@ static void mock_device_release(struct drm_device *dev)
>  	i915_gem_contexts_lost(i915);
>  	mutex_unlock(&i915->drm.struct_mutex);
>  
> -	cancel_delayed_work_sync(&i915->gt.retire_work);
> -	cancel_delayed_work_sync(&i915->gt.idle_work);
> +	drain_delayed_work(&i915->gt.retire_work);
> +	drain_delayed_work(&i915->gt.idle_work);

Yeah, but why in this patch?
-Mika

>  	i915_gem_drain_workqueue(i915);
>  
>  	mutex_lock(&i915->drm.struct_mutex);
> -- 
> 2.20.1