Re: "invalid agent type: 1" in acpi/ghes, cper: Recognize and cache CXL Protocol errors

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Thu, 24 Jul 2025 16:49:00 +0200
"Fabio M. De Francesco" <fabio.m.de.francesco@linux.intel.com> wrote:

> Hi Marc, Smita,
> 
> On Wednesday, July 23, 2025 9:13:34 AM Central European Summer Time Marc Herbert wrote:
> > 
> > On 2025-07-22 12:24, Marc Herbert wrote:  
> > > Hi Smita,
> > > 
> > >   The code below triggers the error "invalid agent type: 1" in Intel
> > > validation (internal issue 15018133056)  
> > 
> > The same test case also triggers the other, warning message "CXL CPER no
> > device serial number".
> > 
> > I heard that "device" serial numbers are only for... devices and that
> > even then it's not always mandatory. So maybe that other message should
> > be downgraded from warning to the "info" level?
> > 
> > Marc
> >  
> 
> [skip]
>  
> > >> +
> > >> +	if (prot_err->err_len != sizeof(struct cxl_ras_capability_regs)) {
> > >> +		pr_err_ratelimited("CXL CPER invalid RAS Cap size (%u)\n",
> > >> +				   prot_err->err_len);
> > >> +		return;
> > >> +	}
> > >> +
> > >> +	if (!(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
> > >> +		pr_warn(FW_WARN "CXL CPER no device serial number\n");
> > >> +  
> 
> Maybe this test should be written on the line of the following snippet taken 
> out from "ACPI: extlog: Trace CPER CXL Protocol Error Section".[1]
> 
> +
> +	if ((prot_err->agent_type == RCD || prot_err->agent_type == DEVICE ||
> +	     prot_err->agent_type == LD || prot_err->agent_type == FMLD) &&
> +	    !(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
> +		pr_warn_ratelimited(FW_WARN
> +				    "CXL CPER no device serial number\n");

They are mandatory for CXL type 3 class code devices (and so the LDs here I think)
Device and RCD might not be type 3 class code so it may be optional?

> +
> 
> Thanks,
> 
> Fabio
> 
> [1] https://lore.kernel.org/linux-cxl/20250623145453.1046660-4-fabio.m.de.francesco@linux.intel.com/
> 
> 
> 
>