śr., 22 cze 2022 o 14:09 Rafael J. Wysocki [off-list ref] napisał(a):

On Tue, Jun 21, 2022 at 1:05 AM Marcin Wojtas [off-list ref] wrote:

quoted

pon., 20 cze 2022 o 19:53 Andy Shevchenko
[off-list ref] napisał(a):

quoted

On Mon, Jun 20, 2022 at 05:02:21PM +0200, Marcin Wojtas wrote:

quoted

The MDIO bus is responsible for probing and registering its respective
children, such as PHYs or other kind of devices.

It is required that ACPI scan code should not enumerate such
devices, leaving this task for the generic MDIO bus routines,
which are initiated by the controller driver.

This patch prevents unwanted enumeration of the devices by setting
'enumeration_by_parent' flag, depending on whether their parent
device is a member of a known list of MDIO controllers. For now,
the Marvell MDIO controllers' IDs are added.

This flag is used for serial buses that are not self-discoverable. Not sure
about MDIO, but the current usage has a relation to the _CRS. Have you
considered to propose the MdioSerialBus() resource type to ACPI specification?

Indeed, one of the cases checked in the
acpi_device_enumeration_by_parent() is checking _CRS (of the bus child
device) for being of the serial bus type. Currently I see
I2C/SPI/UARTSerialBus resource descriptors in the specification. Since
MDIO doesn't seem to require any special description macros like the
mentioned ones (for instance see I2CSerialBusV2 [1]), Based on
example: dfda4492322ed ("ACPI / scan: Do not enumerate Indirect IO
host children"), I thought of similar one perhaps being applicable.

Maybe there is some different, more proper solution, I'd be happy to
hear from the ACPI Maintainers.

[1] https://uefi.org/specs/ACPI/6.4/19_ASL_Reference/ACPI_Source_Language_Reference.html?highlight=i2cserialbus#i2cserialbusterm

Well, the approach based on lists of device IDs is not scalable and
generally used as the last resort one.

It would be a lot better to have a way of representing connections to
the MDIO bus as resources in _CRS.

Thank you for your input. I will submit a proposal for MDIOSerialBus
_CRS resource macro then.

Best regards,
Marcin