[Intel-gfx] [PATCH] drm/i915: Report to userspace if we have a (presumed) working GPU reset

[Daniel Vetter]

On Mon, Jun 15, 2015 at 12:23:48PM +0100, Chris Wilson wrote:
> In igt, we want to test handling of GPU hangs, both for recovery
> purposes and for reporting. However, we don't want to inject a genuine
> GPU hang onto a machine that cannot recover and so be permenantly
> wedged. Rather than embed heuristics into igt, have the kernel report
> exactly when it expects the GPU reset to work.
> 
> This can also be usefully extended in future to indicate different
> levels of fine-grained resets.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Tim Gore <tim.gore at intel.com>
> Cc: Tomas Elf <tomas.elf at intel.com>

Yeah makes sense. Will merge as soon as someone smashes a t-b with a few
igt patches using this on top.
-Daniel
> ---
>  drivers/gpu/drm/i915/i915_dma.c     |  5 +++++
>  drivers/gpu/drm/i915/i915_drv.h     |  1 +
>  drivers/gpu/drm/i915/intel_uncore.c | 28 ++++++++++++++++++++++------
>  include/uapi/drm/i915_drm.h         |  1 +
>  4 files changed, 29 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 34248635c36c..88795d2f1819 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -163,6 +163,11 @@ static int i915_getparam(struct drm_device *dev, void *data,
>  		if (!value)
>  			return -ENODEV;
>  		break;
> +	case I915_PARAM_HAS_GPU_RESET:
> +		value = i915.enable_hangcheck &&
> +			i915.reset &&
> +			intel_has_gpu_reset(dev);
> +		break;
>  	default:
>  		DRM_DEBUG("Unknown parameter %d\n", param->param);
>  		return -EINVAL;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 1110d492ec01..85da0dc3c0e6 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2599,6 +2599,7 @@ extern long i915_compat_ioctl(struct file *filp, unsigned int cmd,
>  			      unsigned long arg);
>  #endif
>  extern int intel_gpu_reset(struct drm_device *dev);
> +extern bool intel_has_gpu_reset(struct drm_device *dev);
>  extern int i915_reset(struct drm_device *dev);
>  extern unsigned long i915_chipset_val(struct drm_i915_private *dev_priv);
>  extern unsigned long i915_mch_val(struct drm_i915_private *dev_priv);
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index 40382bff5ca0..a61de6e944d2 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -1489,20 +1489,36 @@ static int gen6_do_reset(struct drm_device *dev)
>  	return ret;
>  }
>  
> -int intel_gpu_reset(struct drm_device *dev)
> +static int (*intel_get_gpu_reset(struct drm_device *dev))(struct drm_device *)
>  {
>  	if (INTEL_INFO(dev)->gen >= 6)
> -		return gen6_do_reset(dev);
> +		return gen6_do_reset;
>  	else if (IS_GEN5(dev))
> -		return ironlake_do_reset(dev);
> +		return ironlake_do_reset;
>  	else if (IS_G4X(dev))
> -		return g4x_do_reset(dev);
> +		return g4x_do_reset;
>  	else if (IS_G33(dev))
> -		return g33_do_reset(dev);
> +		return g33_do_reset;
>  	else if (INTEL_INFO(dev)->gen >= 3)
> -		return i915_do_reset(dev);
> +		return i915_do_reset;
>  	else
> +		return NULL;
> +}
> +
> +int intel_gpu_reset(struct drm_device *dev)
> +{
> +	int (*reset)(struct drm_device *);
> +
> +	reset = intel_get_gpu_reset(dev);
> +	if (reset == NULL)
>  		return -ENODEV;
> +
> +	return reset(dev);
> +}
> +
> +bool intel_has_gpu_reset(struct drm_device *dev)
> +{
> +	return intel_get_gpu_reset(dev) != NULL;
>  }
>  
>  void intel_uncore_check_errors(struct drm_device *dev)
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 4c3420f932a5..312adbeb4eec 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -354,6 +354,7 @@ typedef struct drm_i915_irq_wait {
>  #define I915_PARAM_REVISION              32
>  #define I915_PARAM_SUBSLICE_TOTAL	 33
>  #define I915_PARAM_EU_TOTAL		 34
> +#define I915_PARAM_HAS_GPU_RESET	 35
>  
>  typedef struct drm_i915_getparam {
>  	int param;
> -- 
> 2.1.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch