[Intel-gfx] [PATCH 1/2] drm/i915: add i915_reset_count

[Damien Lespiau]

On Wed, Oct 30, 2013 at 03:44:15PM +0200, Mika Kuoppala wrote:
> reset_counter will be incremented twice per successful
> reset. Odd values mean reset is in progress and even values
> mean that reset has completed.

Could you also update the lengthy comment above reset_counter. It looks
quite stale. There's also a:

	* Note that the code relies on
	*      I915_WEDGED & I915_RESET_IN_PROGRESS_FLAG
	* being true.

which is not true anymore with this commit. i915_reset_in_progress() has
been modified to take the I915_WEDGED change into account, so we should
be safe, I believe.

With this, you can add a:

Reviewed-by: Damien Lespiau <damien.lespiau at intel.com>

-- 
Damien

> 
> Reset status ioctl introduced in following commit
> needs to deliver global reset count to userspace so
> use reset_counter to derive the actual reset count
> for the gpu
> 
> Note that reset in progress is enough to increment
> the counter.
> 
> v2: wedged equals reset in progress (Daniel Vetter)
> 
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h |   11 ++++++++---
>  drivers/gpu/drm/i915/i915_irq.c |    2 +-
>  2 files changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 0a886fd..9fd716d 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1082,7 +1082,7 @@ struct i915_gpu_error {
>  	 * being true.
>  	 */
>  #define I915_RESET_IN_PROGRESS_FLAG	1
> -#define I915_WEDGED			0xffffffff
> +#define I915_WEDGED			(1 << 31)
>  
>  	/**
>  	 * Waitqueue to signal when the reset has completed. Used by clients
> @@ -2031,12 +2031,17 @@ int __must_check i915_gem_check_wedge(struct i915_gpu_error *error,
>  static inline bool i915_reset_in_progress(struct i915_gpu_error *error)
>  {
>  	return unlikely(atomic_read(&error->reset_counter)
> -			& I915_RESET_IN_PROGRESS_FLAG);
> +			& (I915_RESET_IN_PROGRESS_FLAG | I915_WEDGED));
>  }
>  
>  static inline bool i915_terminally_wedged(struct i915_gpu_error *error)
>  {
> -	return atomic_read(&error->reset_counter) == I915_WEDGED;
> +	return atomic_read(&error->reset_counter) & I915_WEDGED;
> +}
> +
> +static inline u32 i915_reset_count(struct i915_gpu_error *error)
> +{
> +	return ((atomic_read(&error->reset_counter) & ~I915_WEDGED) + 1) / 2;
>  }
>  
>  void i915_gem_reset(struct drm_device *dev);
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index a228176..80800d2 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -1783,7 +1783,7 @@ static void i915_error_work_func(struct work_struct *work)
>  			kobject_uevent_env(&dev->primary->kdev.kobj,
>  					   KOBJ_CHANGE, reset_done_event);
>  		} else {
> -			atomic_set(&error->reset_counter, I915_WEDGED);
> +			atomic_set_mask(I915_WEDGED, &error->reset_counter);
>  		}
>  
>  		/*
> -- 
> 1.7.9.5
> 
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