Re: Research + questions on brcmfmac and support for monitor mode

[Arend van Spriel <arend.vanspriel@broadcom.com>]

On 6/18/2018 1:54 PM, Rafał Miłecki wrote:
> On Mon, 11 Jun 2018 at 12:48, Arend van Spriel
> <arend.vanspriel@broadcom.com> wrote:
>> On 5/30/2018 1:52 PM, Rafał Miłecki wrote:
>>> I'm providing extra version info of tested firmware images as requested
>>> by Arend in another e-mail thread.
>>
>> Looking into our firmware repo it there are two flags, ie. WL_MONITOR
>> and WL_RADIOTAP. It seems both are set for firmware containing -stamon-
>> feature. Your list below confirms that. I still plan to add indication
>> for WL_RADIOTAP in the "cap" iovar, but a stamon feature check could be
>> used for older firmwares.
>
> The problem is that there isn't a direct mapping between what's
> visible with the "tail" command and what firmware returns for the
> "cap" iovar. Just to be sure I bumped #define MAX_CAPS_BUFFER_SIZE to
> 1024. Firmware that has "stamon" when checked with "tail" command
> doesn't report "stamon" over "cap" iovar. So I can't detect if
> firmware was compiled with WL_MONITOR and WL_RADIOTAP using "cap"
> iovar.

All true. My suggestion is to look for "monitor" and "rtap" in the "cap" 
iovar response to detect if firmware is compiled with WL_MONITOR and 
WL_RADIOTAP respectively. When one (or both) of these is not detected, 
we could fallback to try a stamon iovar and if it is supported enable 
both WL_MONITOR and WL_RADIOTAP. I am looking into a good candidate for 
the stamon iovar so I can prepare a patch.

Regards,
Arend