RE: [PATCH v2 05/12] cxl/acpi: Improve debug messages in cxl_acpi_probe()

From: Dan Williams
Date: Thu Oct 20 2022 - 21:00:31 EST


Robert Richter wrote:
> In cxl_acpi_probe() the iterator bus_for_each_dev() walks through all
> CXL hosts. Since all dev_*() debug messages point to the ACPI0017
> device which is the CXL root for all hosts, the device information is
> pointless as it is always the same device. Change this to use the host
> device for this instead.
>
> Also, add additional host specific information such as CXL support,
> UID and CHBCR.
>
> This is an example log:
>
> acpi ACPI0016:00: UID found: 4
> acpi ACPI0016:00: CHBCR found: 0x28090000000
> acpi ACPI0016:00: dport added to root0
> acpi ACPI0016:00: host-bridge: ACPI0016:00
> pci0000:7f: host supports CXL
>
> Signed-off-by: Robert Richter <rrichter@xxxxxxx>
> ---
> drivers/cxl/acpi.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index 31e104f0210f..fb9f72813067 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -221,6 +221,8 @@ static int add_host_bridge_uport(struct device *match, void *arg)
> if (IS_ERR(port))
> return PTR_ERR(port);
>
> + dev_info(pci_root->bus->bridge, "host supports CXL\n");
> +

I generally advocate for drivers to be silent, but this is a fundamental
message in a place that is helpful to indicate whether platform-firmware
is doing its job correctly, and it's only once per host bridge.

Applied for v6.2.