[Intel-gfx] [PATCH 14/19] drm/i915: Forcefully flush GuC log buffer on reset

[Chris Wilson]

On Fri, Aug 19, 2016 at 02:13:13PM +0530, akash.goel at intel.com wrote:
> From: Sagar Arun Kamble <sagar.a.kamble at intel.com>
> 
> Before capturing the GuC logs as a part of error state, there should be a
> force log buffer flush action sent to GuC before proceeding with GPU reset
> and re-initializing GUC. There could be some data in the log buffer which
> is yet to be captured and those logs would be particularly useful to
> understand that why the GPU reset was initiated.

There's no point if we can't wait for any writes to complete, so just take
the snapshot of the log at the time of the hang.

> +void i915_guc_flush_logs(struct drm_i915_private *dev_priv, bool can_wait)
> +{
> +	if (!i915.enable_guc_submission || (i915.guc_log_level < 0))
> +		return;
> +
> +	/* First disable the interrupts, will be renabled afterwards */
> +	gen9_disable_guc_interrupts(dev_priv);

calls synchronize_irq() which is also illegal from the atomic context of
error capture.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre