Re: [PATCH 1/2] drm/xe/xe_ras: Add Fabric error handling

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

On Tue, Sep 01, 2026 at 10:49:28PM +0530, Nilawar, Badal wrote:
> 
> On 27-08-2026 17:58, Rodrigo Vivi wrote:
> > On Thu, Aug 27, 2026 at 04:25:48PM +0530, Aravind Iddamsetty wrote:
> > > On 27-08-2026 02:30, Rodrigo Vivi wrote:
> > > > On Tue, Aug 25, 2026 at 08:20:36PM +0530, Nilawar, Badal wrote:
> > > > > On 25-08-2026 19:41, Riana Tauro wrote:
> > > > > > SAF MHB errors are collected and classifed under Fabric error component
> > > > > > by System controller. For SAF_MHB errors, if the cause is data
> > > > > > payload parity error then log and return.
> > > > > > 
> > > > > > For all other errors and causes, request a Secondary Bus Reset (SBR)
> > > > > > 
> > > > > > Signed-off-by: Riana Tauro <riana.tauro@intel.com>
> > > > > > ---
> > > > > >    drivers/gpu/drm/xe/xe_ras.c       | 20 ++++++++++++++++++++
> > > > > >    drivers/gpu/drm/xe/xe_ras_types.h |  4 ++++
> > > > > >    2 files changed, 24 insertions(+)
> > > > > > 
> > > > > > diff --git a/drivers/gpu/drm/xe/xe_ras.c b/drivers/gpu/drm/xe/xe_ras.c
> > > > > > index d25d25f77531..586dc28a638a 100644
> > > > > > --- a/drivers/gpu/drm/xe/xe_ras.c
> > > > > > +++ b/drivers/gpu/drm/xe/xe_ras.c
> > > > > > @@ -394,6 +394,23 @@ static u8 handle_device_memory_errors(struct xe_device *xe, struct xe_ras_error_
> > > > > >    	return XE_RAS_RECOVERY_ACTION_RECOVERED;
> > > > > >    }
> > > > > > +static u8 handle_fabric_errors(struct xe_device *xe, struct xe_ras_error_array *arr)
> > > > > > +{
> > > > > > +	struct xe_ras_error_product *product = &arr->counter.product;
> > > > > > +	struct xe_ras_ieh_error *info = (void *)arr->details;
> > > > > > +
> > > > > > +	if ((info->global_error_status & XE_RAS_FAB_IEH_SAF_MHB) &&
> > > > > > +	    product->cause.cause == XE_RAS_FAB_CAUSE_PAYLOAD) {
> > > > > > +		xe_log_comp_recoverable(xe, FABRIC, &arr->counter, sizeof(arr->counter),
> > > > > > +					"SAF MHB error detected\n");
> > > > > > +		return XE_RAS_RECOVERY_ACTION_RECOVERED;
> > > > > > +	}
> > > > > > +
> > > > > > +	xe_log_comp_fatal(xe, FABRIC, &arr->counter, sizeof(arr->counter),
> > > > > > +			  "Other errors detected\n");
> > > > > I think this also should go under recoverable.
> > > > The point is that at this moment in time we don't know if the reset will
> > > > indeed be able to recover the device.
> > > I do not think it is right to say that, for any error we sure for know
> > > what is the recovery needed. The respective error handler shall perform
> > > that needed recovery action and anything that is recoverable by a driver
> > > action is to be categorized under RECOVERABLE CPER severity.
> > > 
> > > The case where driver can't recover the device by itself falls into
> > > FATAL case. Eg: probe failure or wedged cases.
> > Fair enough. Riana, could you please adjust both patches?
> > And while at it, please add a note about this in the documentation.
> 
> In addition, rather than hardcoding xe_log_comp_recoverable(), we should
> preserve and utilize the severity reported by firmware:
> 
> static u8 ras_sev_to_cper_sev(u8 ras_sev)
> {
>         switch (ras_sev) {
>         case XE_RAS_SEV_CORRECTABLE:
>                 return CPER_SEV_CORRECTED;
>         case XE_RAS_SEV_UNCORRECTABLE:
>                 return CPER_SEV_RECOVERABLE;
>         case XE_RAS_SEV_INFORMATIONAL:
>                 return CPER_SEV_INFORMATIONAL;
>         default:
>                 return CPER_SEV_RECOVERABLE;
>         }
> }
> 
> Then use
> 
> xe_log_comp(xe, ras_sev_to_cper_sev(severity), FABRIC, &arr->counter,
> sizeof(arr->counter), "Other errors detected\n");
> 
> This keeps the CPER severity aligned with the severity classified by
> firmware while still treating firmware-reported un-correctable errors as
> CPER recoverable.

I like this idea very much! if FW reports let's just map and propagate that.

> 
> Thanks,
> Badal
> 
> > 
> > Thanks,
> > Rodrigo.
> > 
> > > Thanks,
> > > Aravind.
> > > > It is a moment where we are handling a global uncorrectable (fatal) error
> > > > and we will return the reset action in a hope that the PCI subsystem will
> > > > be able to perform an SBR to save the day and we start everything clean
> > > > after that.
> > > > 
> > > > So, I believe this approach is correct here.
> > > > 
> > > > Aravind, thoughts?
> > > > 
> > > > > Thanks,
> > > > > Badal
> > > > > 
> > > > > > +	return XE_RAS_RECOVERY_ACTION_RESET;
> > > > > > +}
> > > > > > +
> > > > > >    void xe_ras_counter_threshold_crossed(struct xe_device *xe,
> > > > > >    				      struct xe_sysctrl_event_response *response)
> > > > > >    {
> > > > > > @@ -555,6 +572,9 @@ enum xe_ras_recovery_action xe_ras_process_errors(struct xe_device *xe)
> > > > > >    			case XE_RAS_COMP_DEVICE_MEMORY:
> > > > > >    				action = handle_device_memory_errors(xe, arr);
> > > > > >    				break;
> > > > > > +			case XE_RAS_COMP_FABRIC:
> > > > > > +				action = handle_fabric_errors(xe, arr);
> > > > > > +				break;
> > > > > >    			default:
> > > > > >    				/* For any other component, reset */
> > > > > >    				action = XE_RAS_RECOVERY_ACTION_RESET;
> > > > > > diff --git a/drivers/gpu/drm/xe/xe_ras_types.h b/drivers/gpu/drm/xe/xe_ras_types.h
> > > > > > index 99b2466e2062..73517fd0d415 100644
> > > > > > --- a/drivers/gpu/drm/xe/xe_ras_types.h
> > > > > > +++ b/drivers/gpu/drm/xe/xe_ras_types.h
> > > > > > @@ -12,6 +12,10 @@
> > > > > >    #define XE_RAS_NUM_ERROR_ARR			3
> > > > > >    /* Error bits in IEH global error status register */
> > > > > >    #define XE_RAS_SOC_IEH_PUNIT			BIT(1)
> > > > > > +/* Bits 16-31 represent individual SAF MHB unit */
> > > > > > +#define XE_RAS_FAB_IEH_SAF_MHB			GENMASK(31, 16)
> > > > Riana, please share where I can check to help reviewing these bits.
> > > > 
> > > > Thanks,
> > > > Rodrigo.
> > > > 
> > > > > > +/* Fabric Data payload parity errors */
> > > > > > +#define XE_RAS_FAB_CAUSE_PAYLOAD		BIT(2)
> > > > > >    /* Device memory error categories */
> > > > > >    #define XE_RAS_MEMORY_DB_ECC			BIT(1)
> > > > > >    #define XE_RAS_MEMORY_POISON			BIT(2)