Re: [PATCH v3 17/18] cxl: Add a dev_dbg() when a decoder was added to a port

Dave Jiang
2025-02-20T17:45:21Z

On 2/11/25 2:53 AM, Robert Richter wrote:
> Improve debugging by adding and unifying messages whenever a decoder
> was added to a port. It is especially useful to get the decoder
> mapping of the involved CXL host bridge or PCI device. This avoids a
> complex lookup of the decoder/port/device mappings in sysfs.
>
> Example log messages:
>
> cxl_acpi ACPI0017:00: decoder0.0 added to root0
> cxl_acpi ACPI0017:00: decoder0.1 added to root0
> ...
> pci0000:e0: decoder1.0 added to port1
> pci0000:e0: decoder1.1 added to port1
> ...
> cxl_mem mem0: decoder5.0 added to endpoint5
> cxl_mem mem0: decoder5.1 added to endpoint5
>
> Signed-off-by: Robert Richter <rrichter@amd.com>
> Reviewed-by: Gregory Price <gourry@gourry.net>
> Tested-by: Gregory Price <gourry@gourry.net>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
> drivers/cxl/acpi.c | 10 +++++++++-
> drivers/cxl/core/hdm.c | 3 ++-
> 2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index cb14829bb9be..3e75e612cbc4 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -421,7 +421,15 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
> rc = cxl_decoder_add(cxld, target_map);
> if (rc)
> return rc;
> - return cxl_root_decoder_autoremove(dev, no_free_ptr(cxlrd));
> +
> + rc = cxl_root_decoder_autoremove(dev, no_free_ptr(cxlrd));
> + if (rc)
> + return rc;
> +
> + dev_dbg(root_port->dev.parent, "%s added to %s\n",
> + dev_name(&cxld->dev), dev_name(&root_port->dev));
> +
> + return 0;
> }
>
> static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index d705dec1471e..467e4fef6a53 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -34,7 +34,8 @@ static int add_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
> if (rc)
> return rc;
>
> - dev_dbg(&cxld->dev, "Added to port %s\n", dev_name(&port->dev));
> + dev_dbg(port->uport_dev, "%s added to %s\n",
> + dev_name(&cxld->dev), dev_name(&port->dev));
>
> return 0;
> }