On 6/23/2023 9:52 AM, Rafael J. Wysocki wrote:
On Wed, Jun 21, 2023 at 7:47 AM Evan Quan <evan.quan@xxxxxxx> wrote:
From: Mario Limonciello <mario.limonciello@xxxxxxx>
Due to electrical and mechanical constraints in certain platform designs
there may be likely interference of relatively high-powered harmonics of
the (G-)DDR memory clocks with local radio module frequency bands used
by Wifi 6/6e/7.
To mitigate this, AMD has introduced an ACPI based mechanism that
devices can use to notify active use of particular frequencies so
that devices can make relative internal adjustments as necessary
to avoid this resonance.
In order for a device to support this, the expected flow for device
driver or subsystems:
Drivers/subsystems contributing frequencies:
1) During probe, check `wbrf_supported_producer` to see if WBRF supported
The prefix should be acpi_wbrf_ or acpi_amd_wbrf_ even, so it is clear
that this uses ACPI and is AMD-specific.
I guess if we end up with an intermediary library approach
wbrf_supported_producer makes sense and that could call acpi_wbrf_*.
But with no intermediate library your suggestion makes sense.
I would prefer not to make it acpi_amd as there is no reason that
this exact same problem couldn't happen on an
Wifi 6e + Intel SOC + AMD dGPU design too and OEMs could use the
same mitigation mechanism as Wifi6e + AMD SOC + AMD dGPU too.
Whether or not there needs to be an intermediate library wrapped
around this is a different matter.
