vc4.ko causes another misterious error

[Ryutaroh Matsumoto]

Hi Stefan and Maxime,

>> The reported problem between 5GHz WiFi and vc4.ko is observed with
>> plain Debian kernel 5.10.24 and Debian firmware-brcm80211 20201218-3.
> this is a kernel mailing list, so we only try to fix kernel issues.
> Firmware issues must be forwarded to the Raspberry Pi foundation who
> finally forward this to Cypress.
> So please stick to firmware-brcm80211 20201218-3 for our investigations
> regarding the 5 GHz issue.

Now I believe that my reported symptom is completely in the brcm firmware files
and not in either brcmfmac.ko or vc4.ko. The reasoning is as follows:

The reported symptom completely went away by replacing
/lib/firmware/brcm/brcmfmac43455-sdio.bin and
/lib/firmware/brcm/brcmfmac43455-sdio.clm_blob
by the files at
https://github.com/RPi-Distro/firmware-nonfree/tree/master/brcm

Commit messages at https://github.com/RPi-Distro/firmware-nonfree/tree/master/brcm
are interesting:

Use BCM43456 clm_blob on CYW43455
The previous CYW43455 clm_blob provides limited access to the higher
5GHz channels (100+) - the BCM43456 (surprisingly) seems to work and
doesn't have this problem. Huh????

Update CYW43455 firmware
This release fixes the error: Firmware trap: type 0x4 @ epc 0x0007a094
The full version string is:
Version 7.45.229 (617f1f5 CY) CRC: 253bd863 Date: Mon 2021-01-04 19:58:58 PST Ucode Ver: 1043.2160 FWID 01-2dbd9d2e
See: raspberrypi/linux#3849

> this is a kernel mailing list, so we only try to fix kernel issues.
> Firmware issues must be forwarded to the Raspberry Pi foundation who
> finally forward this to Cypress.

I also sent the above observation to the Debian firmware package maintainers...

Best regards,
Ryutaroh Matsumoto