Re: [PATCH] drm/i915: Clear pending reset requests during suspend

From: Daniel Vetter <daniel@ffwll.ch>
To: Arun Siluvery <arun.siluvery@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org, Mika Kuoppala <mika.kuoppala@intel.com>
Subject: Re: [PATCH] drm/i915: Clear pending reset requests during suspend
Date: Tue, 19 Jan 2016 13:09:28 +0100	[thread overview]
Message-ID: <20160119120928.GC19130@phenom.ffwll.local> (raw)
In-Reply-To: <1452768585-18661-1-git-send-email-arun.siluvery@linux.intel.com>

On Thu, Jan 14, 2016 at 10:49:45AM +0000, Arun Siluvery wrote:
> Pending reset requests are cleared before suspending, they should be picked up
> after resume when new work is submitted.
> 
> This is originally added as part of TDR patches for Gen8 from Tomas Elf which
> are under review, as suggested by Chris this is extracted as a separate patch
> as it can be useful now.
> 
> Cc: Mika Kuoppala <mika.kuoppala@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>

Pulling in the discussion we had from irc: Imo the right approach is to
simply wait for gpu reset to finish it's job. Since that could in turn
lead to a dead gpu (if we're unlucky and init_hw failed) we'd need to do
that in a loop around gem_idle. And drop dev->struct_mutex in-between.
E.g.

while (busy) {
	mutex_lock();
	gpu_idle();
	mutex_unlock();

	flush_work(reset_work);
}

Cheers, Daniel
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index f17a2b0..09ed83e 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -594,6 +594,13 @@ static int i915_drm_suspend(struct drm_device *dev)
>  		goto out;
>  	}
>  
> +	/*
> +	 * Clear any pending reset requests. They should be picked up
> +	 * after resume when new work is submitted
> +	 */
> +	atomic_clear_mask(I915_RESET_IN_PROGRESS_FLAG,
> +			  &dev_priv->gpu_error.reset_counter);
> +
>  	intel_guc_suspend(dev);
>  
>  	intel_suspend_gt_powersave(dev);
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

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