[Intel-gfx] [PATCH v8 2/8] drm/i915: Update GEM suspend/resume flows considering GuC and GEM fences

[Chris Wilson]

Quoting Sagar Arun Kamble (2017-09-26 14:24:39)
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index dbe181b..5dcd8c0 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2022,11 +2022,22 @@ int i915_gem_fault(struct vm_fault *vmf)
>         intel_runtime_pm_put(i915);
>  }
>  
> +/**
> + * i915_gem_runtime_suspend() - Finish GEM suspend
> + * @dev_priv: i915 device private
> + *
> + * This function suspends GuC, removes userspace mappings for all GEM obejcts
> + * currently on userfault list and marks fences if any being used as lost.
> + *
> + * Return:     non-zero code on error
> + */

> +/**
> + * i915_gem_runtime_resume() - Restore GEM state
> + * @dev_priv: i915 device private
> + *
> + * This function inits swizzling, restores fences and resumes GuC.
> + *
> + * Return:     non-zero code on error
> + */

> +/**
> + * i915_gem_suspend() - Suspend all GT activity.
> + * @dev_priv: i915 device private
> + *
> + * This function disables RPS, flushes all executing context ensuring
> + * GEM/GT/Engines idleness, cancels all work that needs GT access and suspends
> + * GuC. In the end currently, it also reset the GEM state and GPU HW.
> + *
> + * Return:     non-zero code on error
> + */

> +/**
> + * i915_gem_resume() - Resume GT activity.
> + * @dev_priv: i915 device private
> + *
> + * This function restores GTT mappings, restores fences and resets the
> + * context images and resumes GuC.
> + *
> + * Return:     non-zero code on error
> + */

I can very much read what the functions do. These comments blocks are
for telling me when to call them, under what pre/post-conditions and the
overall intent of the function.

Who are these blocks for? This isn't a library interface we expect to be
used, these are hooks.
-Chris