Re: [PATCH 03/12] drm/i915/guc: Do not wait for firmware load atomically

From: Dave Gordon <david.s.gordon@intel.com>
To: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
	Intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 03/12] drm/i915/guc: Do not wait for firmware load atomically
Date: Tue, 2 Feb 2016 14:13:37 +0000	[thread overview]
Message-ID: <56B0B991.4080901@intel.com> (raw)
In-Reply-To: <1454411190-15721-4-git-send-email-tvrtko.ursulin@linux.intel.com>

On 02/02/16 11:06, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>
> It does not look like this code needs to wait atomically?
>
> Higher in the call chain it calls the GEM API and I do
> not see that the section is under any spin locks or such.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Cc: Alex Dai <yu.dai@intel.com>
> ---
>   drivers/gpu/drm/i915/intel_guc_loader.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
> index 3accd914490f..82a3c03fbc0e 100644
> --- a/drivers/gpu/drm/i915/intel_guc_loader.c
> +++ b/drivers/gpu/drm/i915/intel_guc_loader.c
> @@ -199,7 +199,7 @@ static void set_guc_init_params(struct drm_i915_private *dev_priv)
>    * the value matches either of two values representing completion
>    * of the GuC boot process.
>    *
> - * This is used for polling the GuC status in a wait_for_atomic()
> + * This is used for polling the GuC status in a wait_for()
>    * loop below.
>    */
>   static inline bool guc_ucode_response(struct drm_i915_private *dev_priv,
> @@ -259,14 +259,14 @@ static int guc_ucode_xfer_dma(struct drm_i915_private *dev_priv)
>   	I915_WRITE(DMA_CTRL, _MASKED_BIT_ENABLE(UOS_MOVE | START_DMA));
>
>   	/*
> -	 * Spin-wait for the DMA to complete & the GuC to start up.
> +	 * Wait for the DMA to complete & the GuC to start up.
>   	 * NB: Docs recommend not using the interrupt for completion.
>   	 * Measurements indicate this should take no more than 20ms, so a
>   	 * timeout here indicates that the GuC has failed and is unusable.
>   	 * (Higher levels of the driver will attempt to fall back to
>   	 * execlist mode if this happens.)
>   	 */
> -	ret = wait_for_atomic(guc_ucode_response(dev_priv, &status), 100);
> +	ret = wait_for(guc_ucode_response(dev_priv, &status), 100);
>
>   	DRM_DEBUG_DRIVER("DMA status 0x%x, GuC status 0x%x\n",
>   			I915_READ(DMA_CTRL), status);

LGTM.

Reviewed-by: Dave Gordon <david.s.gordon@intel.com>

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