Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Merge r232250 from head:

Correct capitalization of "Hz" in user-visible text (manpages, printf(),
etc).

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Reset the NIC if ANI is enabled or disabled.

Although this may not be what the original sysctl was designed to do,
it feels a bit more "expected".

Before, if ANI is disabled, the initial ANI parameters are still written
to the hardware, even if they're not enabled. "ANI enabled" would then
adjust the noise immunity parameters dynamically. Disabling ANI would
simply leave the existing noise immunity parameters where they are,
and disable the dynamic part.

The problem is that disabling ANI doesn't leave the hardware in
a consistent, predictable state - so asking a user to disable ANI
wouldn't actually reset the NIC to a consistent set of PHY signal
detection parameters, resulting in an unpredictable/unreliable outcome.
This makes it difficult to get reliable debugging information from
the user.

Approved by: re (kib)

Break out most of the HAL related tweaks into a per-HAL instance,
rather than global variables.

This specifically allows for debugging to be enabled per-NIC, rather
than globally.

Since the ath driver doesn't know about AH_DEBUG, and to keep the ABI
consistent regardless of whether AH_DEBUG is enabled or not, enable the
debug parameter always but only conditionally compile in the debug
methods if needed.

The ALQ support is currently still global pending some brainstorming.

Submitted by: ssgriffonuser@gmail.com
Reviewed by: adrian, bschmidt

* Add some more TX descriptor error counters; this'll be helpful when
implementing TX aggregation
* Whilst I'm there, comment some RX error counters

Add TX carrier sense timeout statistics.

Add global TX timeout handling.

The global TX timeout counter increments whenever a frame is ready
to be transmitted and the medium is busy.

According to ath9k recv.c, one shouldn't be doing self-linked descriptors
in the RX path when doing 11n and block-ack'ed frames. Apparently, the MAC
will loop over that self-linked descriptor and treat it as "good enough"
for (incorrectly!) ACKing the frames in the block-ack.

Until I figure out how to work around this issue in the future, this counter
will tell me if packet RX processing ever gets to the point where it's
touching the self-linked descriptor. If there's ever enough packets to get
to that point, BA's will be invalid and likely very unhappy.

Migrate the sysctl related routines (statistics, debugging, etc) out of
if_ath.c and into if_ath_sysctl.c .