[PATCH v5] drm/xe/uc: Disable GuC communication on hardware initialization error.

[Cavitt, Jonathan]

-----Original Message-----
From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Zhanjun Dong
Sent: Wednesday, June 18, 2025 4:33 PM
To: intel-xe at lists.freedesktop.org
Cc: Dong, Zhanjun <zhanjun.dong at intel.com>; Wajdeczko, Michal <Michal.Wajdeczko at intel.com>; Summers, Stuart <stuart.summers at intel.com>
Subject: [PATCH v5] drm/xe/uc: Disable GuC communication on hardware initialization error.
> 
> Disable GuC communication on Xe micro controller hardware initialization
> error.
> 
> Signed-off-by: Zhanjun Dong <zhanjun.dong at intel.com>
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4917
> 
> ---
> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Stuart Summers <stuart.summers at intel.com>
> 
> Change list:
> v5: Set wedge is excessive action, revert back to disable ct
> v4: Fix typo and add new line
> v3: v2 CI re-run
> v2: Remove unnecessary jump to err-out
>     Drop disable ct, switch to set wedge
> ---
>  drivers/gpu/drm/xe/xe_guc.c |  5 +++++
>  drivers/gpu/drm/xe/xe_guc.h |  1 +
>  drivers/gpu/drm/xe/xe_uc.c  | 23 ++++++++++++++++-------
>  3 files changed, 22 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> index 209e5d53c290..9d7175b16cc7 100644
> --- a/drivers/gpu/drm/xe/xe_guc.c
> +++ b/drivers/gpu/drm/xe/xe_guc.c
> @@ -1230,6 +1230,11 @@ int xe_guc_enable_communication(struct xe_guc *guc)
>  	return 0;
>  }
>  
> +void xe_guc_disable_communication(struct xe_guc *guc)
> +{
> +	xe_guc_ct_disable(&guc->ct);
> +}
> +
>  int xe_guc_suspend(struct xe_guc *guc)
>  {
>  	struct xe_gt *gt = guc_to_gt(guc);
> diff --git a/drivers/gpu/drm/xe/xe_guc.h b/drivers/gpu/drm/xe/xe_guc.h
> index 58338be44558..285c19929f8c 100644
> --- a/drivers/gpu/drm/xe/xe_guc.h
> +++ b/drivers/gpu/drm/xe/xe_guc.h
> @@ -33,6 +33,7 @@ int xe_guc_reset(struct xe_guc *guc);
>  int xe_guc_upload(struct xe_guc *guc);
>  int xe_guc_min_load_for_hwconfig(struct xe_guc *guc);
>  int xe_guc_enable_communication(struct xe_guc *guc);
> +void xe_guc_disable_communication(struct xe_guc *guc);
>  int xe_guc_suspend(struct xe_guc *guc);
>  void xe_guc_notify(struct xe_guc *guc);
>  int xe_guc_auth_huc(struct xe_guc *guc, u32 rsa_addr);
> diff --git a/drivers/gpu/drm/xe/xe_uc.c b/drivers/gpu/drm/xe/xe_uc.c
> index 3a8751a8b92d..35cf67b2c2f8 100644
> --- a/drivers/gpu/drm/xe/xe_uc.c
> +++ b/drivers/gpu/drm/xe/xe_uc.c
> @@ -13,6 +13,7 @@
>  #include "xe_gt_printk.h"
>  #include "xe_gt_sriov_vf.h"
>  #include "xe_guc.h"
> +#include "xe_guc_ct.h"
>  #include "xe_guc_pc.h"
>  #include "xe_guc_engine_activity.h"
>  #include "xe_huc.h"
> @@ -157,19 +158,23 @@ static int vf_uc_init_hw(struct xe_uc *uc)
>  
>  	err = xe_guc_enable_communication(&uc->guc);
>  	if (err)
> -		return err;
> +		goto err_out;

I feel like if xe_guc_enable_communication fails, we shouldn't need to 
disable it afterwards, as it should already not be enabled.  Specifically,
xe_guc_enable_communication fails only when xe_guc_ct_enable fails,
which would indicate that it wasn't enabled.

Well... okay, xe_guc_enable_communication can also return an error
value if xe_memirq_init_guc fails, but this is only the case for systems
where IS_SRIOV_VF and xe_device_has_memirq return true, which
isn't a significant subset of systems.  And besides that, if
xe_memirq_init_guc fails, then we don't even run xe_guc_ct_enable.

So, either way, the GuC CT shouldn't have been enabled if
xe_guc_enable_communication failed.  Ergo, we shouldn't need to
call xe_guc_ct_disable to disable a GuC CT that failed to be enabled.

Though maybe we need to very specifically xe_guc_ct_set_state here
to declare the CT as disabled to GuC so it doesn't try to access it?  I can
see that being the case.

If this needs to be fixed, then fix it first, but otherwise:
Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
-Jonathan Cavitt

>  
>  	err = xe_gt_sriov_vf_connect(uc_to_gt(uc));
>  	if (err)
> -		return err;
> +		goto err_out;
>  
>  	uc->guc.submission_state.enabled = true;
>  
>  	err = xe_gt_record_default_lrcs(uc_to_gt(uc));
>  	if (err)
> -		return err;
> +		goto err_out;
>  
>  	return 0;
> +
> +err_out:
> +	xe_guc_disable_communication(&uc->guc);
> +	return err;
>  }
>  
>  /*
> @@ -197,19 +202,19 @@ int xe_uc_init_hw(struct xe_uc *uc)
>  
>  	ret = xe_guc_enable_communication(&uc->guc);
>  	if (ret)
> -		return ret;
> +		goto err_out;
>  
>  	ret = xe_gt_record_default_lrcs(uc_to_gt(uc));
>  	if (ret)
> -		return ret;
> +		goto err_out;
>  
>  	ret = xe_guc_post_load_init(&uc->guc);
>  	if (ret)
> -		return ret;
> +		goto err_out;
>  
>  	ret = xe_guc_pc_start(&uc->guc.pc);
>  	if (ret)
> -		return ret;
> +		goto err_out;
>  
>  	xe_guc_engine_activity_enable_stats(&uc->guc);
>  
> @@ -221,6 +226,10 @@ int xe_uc_init_hw(struct xe_uc *uc)
>  	xe_gsc_load_start(&uc->gsc);
>  
>  	return 0;
> +
> +err_out:
> +	xe_guc_disable_communication(&uc->guc);
> +	return ret;
>  }
>  
>  int xe_uc_fini_hw(struct xe_uc *uc)
> -- 
> 2.34.1
> 
>