Re: [PATCH v2] cxl/pci: Honor -EPROBE_DEFER from component register setup

On Mon, Jul 06, 2026 at 03:43:22PM -0700, Dave Jiang wrote:
> cxl_pci_setup_regs() for CXL_REGLOC_RBI_COMPONENT can return
> -EPROBE_DEFER on a Restricted CXL Host (RCD) when the upstream port
> has not yet been enumerated and the Component Registers must be
> extracted from the RCRB. cxl_pci_probe() treats every non-zero return
> from that call as the benign "component registers not found" case,
> logs a warning, and continues. The rc is then immediately overwritten
> by the subsequent cxl_pci_type3_init_mailbox() call, so the deferral
> is silently swallowed.
> 
> Return -EPROBE_DEFER instead of continuing so the probe is retried
> once the upstream port is available.

Let's get this one merged, and go after the Sashiko pre-existing
issue in new patch.

Reviewed-by: Alison Schofield <[email protected]>


> 
> Fixes: 733b57f262b0 ("cxl/pci: Early setup RCH dport component registers from RCRB")
> Reported-by: [email protected]
> Closes: https://lore.kernel.org/linux-cxl/ajzhsubot_PSYtHQ@MWDK4CY14F/T/#m063bbf76b1c9c293ade52ab311018ae6bba11a44
> Assisted-by: Claude:claude-opus-4-8
> Signed-off-by: Dave Jiang <[email protected]>
> ---
>  drivers/cxl/pci.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 267c679b0b3c..6a132a6c4c5b 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -829,10 +829,13 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  	 */
>  	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT,
>  				&cxlds->reg_map);
> -	if (rc)
> +	if (rc) {
> +		if (rc == -EPROBE_DEFER)
> +			return rc;
>  		dev_warn(&pdev->dev, "No component registers (%d)\n", rc);
> -	else if (!cxlds->reg_map.component_map.ras.valid)
> +	} else if (!cxlds->reg_map.component_map.ras.valid) {
>  		dev_dbg(&pdev->dev, "RAS registers not found\n");
> +	}
>  
>  	rc = cxl_pci_type3_init_mailbox(cxlds);
>  	if (rc)
> 
> base-commit: 8cdeaa50eae8dad34885515f62559ee83e7e8dda
> -- 
> 2.54.0
> 
>