Re: [PATCH v2] drm/i915: Increase FLR timeout from 3s to 9s

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, May 24, 2024 at 01:58:53AM +0200, Andi Shyti wrote:
> Following the guidelines it takes 3 seconds to perform an FLR
> reset. Let's give it a bit more slack because this time can
> change depending on the platform and on the firmware

But did we see any issue with that?

if that changes per platform and per firmware, shouldn't it all
be explicit in the spec as well?

> 
> Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
> ---
> Hi,
> 
> In this second version I removed patch 2 that was ignoring the
> FLR reset timeouts, until we develop a proper patch.
> 
> This first patch is basically the same as v1. Thanks Nirmoy for
> your review.
> 
> Andi
> 
>  drivers/gpu/drm/i915/intel_uncore.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index 729409a4bada..2eba289d88ad 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -2614,11 +2614,18 @@ void intel_uncore_prune_engine_fw_domains(struct intel_uncore *uncore,
>  static void driver_initiated_flr(struct intel_uncore *uncore)
>  {
>  	struct drm_i915_private *i915 = uncore->i915;
> -	const unsigned int flr_timeout_ms = 3000; /* specs recommend a 3s wait */
> +	unsigned int flr_timeout_ms;
>  	int ret;
>  
>  	drm_dbg(&i915->drm, "Triggering Driver-FLR\n");
>  
> +	/*
> +	 * The specification recommends a 3 seconds FLR reset timeout. To be
> +	 * cautious, we will extend this to 9 seconds, three times the specified
> +	 * timeout.
> +	 */
> +	flr_timeout_ms = 9000;
> +
>  	/*
>  	 * Make sure any pending FLR requests have cleared by waiting for the
>  	 * FLR trigger bit to go to zero. Also clear GU_DEBUG's DRIVERFLR_STATUS
> -- 
> 2.45.1
>