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authorDave Airlie <airlied@redhat.com>2023-12-19 22:59:40 +0300
committerDave Airlie <airlied@redhat.com>2023-12-19 22:59:41 +0300
commitd2be61f8438feb2e356187acdfeef26fd777602a (patch)
tree0b799793dd72b5f8e39bb88b85408d27353ad766 /Documentation
parent48b272853e5ca6680eb7d019347126923da1a2eb (diff)
parent669080888691c312cc926322a7b24600121c90fb (diff)
downloadlinux-d2be61f8438feb2e356187acdfeef26fd777602a.tar.xz
Merge tag 'amd-drm-next-6.8-2023-12-15' of https://gitlab.freedesktop.org/agd5f/linux into drm-next
amd-drm-next-6.8-2023-12-15: amdgpu: - Suspend fixes - Misc code cleanups - JPEG fix - Add AMD specific color management (protected by AMD_PRIVATE_COLOR) - UHBR13.5 cable fixes - Misc display fixes - Display WB fixes - PSR fixes - XGMI fix - ACPI WBRF support for handling potential RF interference from GPU clocks - Enable tunneling on high priority compute queues - drm_edid.h include cleanup - VPE DPM support - SMU 13 fixes - Fix possible double frees in error paths - Misc fixes amdkfd: - Support import and export of dma-bufs using GEM handles - MES shader debugger fixes - SVM fixes radeon: - drm_edid.h include cleanup - Misc code cleanups - Fix possible memory leak in error path drm: - Increase max objects to accomodate new color props - Make replace_property_blob_from_id a DRM helper - Track color management changes per plane platform-x86: - Merge immutable branch from Hans for platform dependencies for WBRF to coordinate merge of WBRF feature across wifi, platform, and GPU Signed-off-by: Dave Airlie <airlied@redhat.com> # -----BEGIN PGP SIGNATURE----- # # iHUEABYKAB0WIQQgO5Idg2tXNTSZAr293/aFa7yZ2AUCZXygTgAKCRC93/aFa7yZ # 2EW1AQCILfGTtDWXzgLSpUBtt9jOooHqaSrah19Cfw0HlA3QIQD+OCohXH1LLZo1 # tYHyfsLv0LsNawI198qABzB1PwptSAI= # =M1AO # -----END PGP SIGNATURE----- # gpg: Signature made Sat 16 Dec 2023 04:51:58 AEST # gpg: using EDDSA key 203B921D836B5735349902BDBDDFF6856BBC99D8 # gpg: Can't check signature: No public key From: Alex Deucher <alexander.deucher@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20231215193519.5040-1-alexander.deucher@amd.com
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/driver-api/index.rst1
-rw-r--r--Documentation/driver-api/wbrf.rst78
2 files changed, 79 insertions, 0 deletions
diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
index f549a68951d7..8bc4ebe7a36f 100644
--- a/Documentation/driver-api/index.rst
+++ b/Documentation/driver-api/index.rst
@@ -115,6 +115,7 @@ available subsections can be seen below.
hte/index
wmi
dpll
+ wbrf
.. only:: subproject and html
diff --git a/Documentation/driver-api/wbrf.rst b/Documentation/driver-api/wbrf.rst
new file mode 100644
index 000000000000..f48bfa029813
--- /dev/null
+++ b/Documentation/driver-api/wbrf.rst
@@ -0,0 +1,78 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+=================================
+WBRF - Wifi Band RFI Mitigations
+=================================
+
+Due to electrical and mechanical constraints in certain platform designs
+there may be likely interference of relatively high-powered harmonics of
+the GPU memory clocks with local radio module frequency bands used by
+certain Wifi bands.
+
+To mitigate possible RFI interference producers can advertise the
+frequencies in use and consumers can use this information to avoid using
+these frequencies for sensitive features.
+
+When a platform is known to have this issue with any contained devices,
+the platform designer will advertise the availability of this feature via
+ACPI devices with a device specific method (_DSM).
+* Producers with this _DSM will be able to advertise the frequencies in use.
+* Consumers with this _DSM will be able to register for notifications of
+frequencies in use.
+
+Some general terms
+==================
+
+Producer: such component who can produce high-powered radio frequency
+Consumer: such component who can adjust its in-use frequency in
+response to the radio frequencies of other components to mitigate the
+possible RFI.
+
+To make the mechanism function, those producers should notify active use
+of their particular frequencies so that other consumers can make relative
+internal adjustments as necessary to avoid this resonance.
+
+ACPI interface
+==============
+
+Although initially used by for wifi + dGPU use cases, the ACPI interface
+can be scaled to any type of device that a platform designer discovers
+can cause interference.
+
+The GUID used for the _DSM is 7B7656CF-DC3D-4C1C-83E9-66E721DE3070.
+
+3 functions are available in this _DSM:
+
+* 0: discover # of functions available
+* 1: record RF bands in use
+* 2: retrieve RF bands in use
+
+Driver programming interface
+============================
+
+.. kernel-doc:: drivers/platform/x86/amd/wbrf.c
+
+Sample Usage
+=============
+
+The expected flow for the producers:
+1. During probe, call `acpi_amd_wbrf_supported_producer` to check if WBRF
+can be enabled for the device.
+2. On using some frequency band, call `acpi_amd_wbrf_add_remove` with 'add'
+param to get other consumers properly notified.
+3. Or on stopping using some frequency band, call
+`acpi_amd_wbrf_add_remove` with 'remove' param to get other consumers notified.
+
+The expected flow for the consumers:
+1. During probe, call `acpi_amd_wbrf_supported_consumer` to check if WBRF
+can be enabled for the device.
+2. Call `amd_wbrf_register_notifier` to register for notification
+of frequency band change(add or remove) from other producers.
+3. Call the `amd_wbrf_retrieve_freq_band` initally to retrieve
+current active frequency bands considering some producers may broadcast
+such information before the consumer is up.
+4. On receiving a notification for frequency band change, run
+`amd_wbrf_retrieve_freq_band` again to retrieve the latest
+active frequency bands.
+5. During driver cleanup, call `amd_wbrf_unregister_notifier` to
+unregister the notifier.