[Intel-gfx] [PATCH] drm/i915/guc: Add debug capture of GuC exception

[Michal Wajdeczko]

On Fri, 21 Jun 2019 22:09:40 +0200, Robert M. Fosha  
<robert.m.fosha at intel.com> wrote:

> Detect GuC firmware load failure due to an exception during execution
> in GuC firmware. Output the GuC EIP where excpetion occured to dmesg

two typos here

> for GuC debug information.
>
> Signed-off-by: Robert M. Fosha <robert.m.fosha at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_guc_fw.c  | 7 +++++++
>  drivers/gpu/drm/i915/intel_guc_reg.h | 1 +
>  2 files changed, 8 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_guc_fw.c  
> b/drivers/gpu/drm/i915/intel_guc_fw.c
> index 72cdafd9636a..90cb65641d60 100644
> --- a/drivers/gpu/drm/i915/intel_guc_fw.c
> +++ b/drivers/gpu/drm/i915/intel_guc_fw.c
> @@ -197,6 +197,7 @@ static inline bool guc_ready(struct intel_guc *guc,  
> u32 *status)
> static int guc_wait_ucode(struct intel_guc *guc)
>  {
> +	struct drm_i915_private *i915 = guc_to_i915(guc);
>  	u32 status;
>  	int ret;
> @@ -216,6 +217,12 @@ static int guc_wait_ucode(struct intel_guc *guc)
>  		ret = -ENOEXEC;
>  	}
> +	if ((status & GS_UKERNEL_MASK) == GS_UKERNEL_EXCEPTION) {

I guess GuC exception could also happen after fw boot time,
can we add support to detect and log such exceptions?
and maybe such unified approach will cover this case as well?

> +		DRM_ERROR("GuC fw exception. GuC uKernel EIP: %#x\n",

do we need to use two names "fw" and "uKernel" here? maybe just:

	DRM_ERROR("GuC firmware exception. EIP: %#x\n",

> +			  intel_uncore_read(&i915->uncore, SOFT_SCRATCH(13)));
> +		ret = -ENOEXEC;

as this is not a blob problem, maybe -ENXIO will fit better ?

> +	}
> +
>  	if (ret == 0 && !guc_xfer_completed(guc, &status)) {
>  		DRM_ERROR("GuC is ready, but the xfer %08x is incomplete\n",
>  			  status);
> diff --git a/drivers/gpu/drm/i915/intel_guc_reg.h  
> b/drivers/gpu/drm/i915/intel_guc_reg.h
> index a214f8b71929..d90b88fadb5e 100644
> --- a/drivers/gpu/drm/i915/intel_guc_reg.h
> +++ b/drivers/gpu/drm/i915/intel_guc_reg.h
> @@ -37,6 +37,7 @@
>  #define   GS_UKERNEL_MASK		  (0xFF << GS_UKERNEL_SHIFT)
>  #define   GS_UKERNEL_LAPIC_DONE		  (0x30 << GS_UKERNEL_SHIFT)
>  #define   GS_UKERNEL_DPC_ERROR		  (0x60 << GS_UKERNEL_SHIFT)
> +#define   GS_UKERNEL_EXCEPTION		  (0x70 << GS_UKERNEL_SHIFT)
>  #define   GS_UKERNEL_READY		  (0xF0 << GS_UKERNEL_SHIFT)
>  #define   GS_MIA_SHIFT			16
>  #define   GS_MIA_MASK			  (0x07 << GS_MIA_SHIFT)