from patchwork.kernel.org:
The linux-firmware brcmfmac firmware files contain an embedded table with
per country allowed channels and strength info.
These versions of the firmware are specially build for linux-firmware,
the firmware files directly available from Broadcom / Cypress rely on
a separate clm_blob file for this info.
For some unknown reason Broadcom / Cypress refuse to provide the standard
firmware files + clm_blob files it uses elsewhere for inclusion into
linux-firmware, instead relying on these special builds with the clm_blob
info embedded. This means that the linux-firmware firmware versions often
lag behind, but I digress.
The brcmfmac driver does support the separate clm_blob file and always
tries to load this. Currently we use request_firmware for this. This means
that on any standard install, using the standard combo of linux-kernel +
linux-firmware, we will get a warning:
"Direct firmware load for ... failed with error -2"
On top of this, brcmfmac itself prints: "no clm_blob available (err=-2),
device may have limited channels available" and we will get a slow
fallback to the userspace firmware loading mechanism.
This commit fixes both almost any brcmfmac device logging the warning
(leaving the brcmfmac info message in pace), as well as the slow and
unnecesary fallback by switching to request_firmware_direct for
the clm_blob.
d4e7e07a39