leds_dump() printed the pin mux, the LED enables and every LED set on each
boot, from BANK2. It now lives in its own file in BANK3, where there is
room, and runs only on the new "leds" command, next to gpio and sds, so it
stays at hand for bringing up a new board without costing BANK2 or boot
output.
494320b removed strcpy() from rtl837x_flash.c but left its declaration
in rtl837x_common.h. Since then the linker has taken strcpy from the
SDCC library instead, which expects the destination as a generic pointer
in DPL, DPH and B. The callers pass an __xdata pointer and leave B as it
is, so the copy lands wherever B happens to point. boot.c only gets away
with it because B is zero there; a call with B set, as from the ChaCha20
test in #207, writes into internal RAM and stops the 8051.
Only frames to 01:00:5e:00:00:16 reached the IGMP handler, so v1/v2
reports, which go to the group address, were never seen. The handler
also took the group from the first v3 group record for every type.
Pass all IPv4 multicast to the handler, which takes the IGMP header
from the IP header length, the group from the IGMP header for v1/v2
reports and v2 leaves and from the first group record for v3, and
returns 0 for anything that is not IGMP so it goes on to the IP stack.
The message and record types have names now.
The main loop drains the NIC only after an RX interrupt, at most
RX_BUDGET frames, then clears the status and waits for the next one.
When frames are left and the buffer reaches the RX stop threshold, the
NIC takes no more frames and raises no further interrupt, so reception
stops for good.
Check the buffer after clearing the status and keep draining while it
holds data; the interrupt is re-enabled only once it is empty.
rtl8224_enable() waits 2.5 s after releasing the RTL8224 reset before
anything talks to the PHY. On an SWTGW218AS the chip id already reads
back 0x8224 at the first poll, about 265 ms after the release.
Remember when the reset was released and, once SMI is up, poll the chip
id until it answers, giving up after the same 2.5 s as before. The PHY
writes that follow read back the same as before.
The reset pulse before it goes from 0.5 s to 20 ms, twice the 10 ms the
related RTL8372 and RTL8221B need. The pulse does reset the chip: the
MDI reverse register (MMD 30, 0x0a90) still reads its power-on value
0x00f3 just before the init writes 0x00fc, as it does with 0.5 s.
Together the console banner comes 3 s sooner.
The SerDes write loop in phy_config_8224() waited on the busy bit with
no limit, so a PHY that never answers stopped the boot before the
network came up. Bound it and report a timeout.
The receive interrupt was wired up but never used: EX1 was enabled, the
handler re-enabled itself and did nothing, and the mask bit for it in the
NIC stayed clear, so idle() read the receive buffer register on every
pass to find out whether a packet had arrived, and slept until the next
tick when none had. A packet that arrived during that sleep waited for
the tick: 2.2 ms on average, 5 ms at worst, for every frame the CPU
handles.
Now the handler latches rx_irq and masks itself, and idle() sleeps
unless a receive, a link change, a console command or the tick is
pending. On rx_irq the loop drains the buffer, clears the status bit and
re-enables EX1, in that order: the NIC holds the line as long as the
status bit is set, and the bit does not clear while the buffer still
holds a frame, so a frame that lands between the last read and EX1 = 1
raises the interrupt again rather than getting lost. The other order,
clearing before draining, left the line asserted and produced an
interrupt on every pass. The mask is written after nic_setup(), which
resets it.
Measured on an RTL8373 board with the same counters in both images,
clocked by the tick counter, traffic from a host behind an LACP trunk:
```
polling interrupt
idle, register ops/s 788 79
25 pps, RTT avg/max 2.19/4.96 0.44/0.75 ms
500 pps, RTT avg/max 2.78/5.06 0.39/5.40 ms
500 pps, loss 0.08% 0.08%
```
The handler compiles to clr EX1 / setb rx_irq / reti.
The timer interrupt now raises a tick flag too, so idle() no longer works
out TICKS_DUE twice per pass, and cmd_available moves from xdata to a
bit. The four wake-up flags sit in the low bits of one byte at 0x20, so
the sleep test is a single read of that byte. tx_buf_empty deliberately
stays out: it is 1 when there is nothing to do, so including it would
keep the sleep test from ever firing.
idle() ran everything on every pass: the seconds block, the SFP pin
test, the TCP periodic timer behind a gate of its own, the STP timers
behind theirs. The timed work moves into handle_tick(), which idle()
calls once per system tick from a single gate; handle_tx() loses its
private one.
handle_sfp() ran on every pass as well, two GPIO reads per pass to learn
that nothing changed; it now runs every ten ticks. A module inserted is
still seen within 50 ms, and the read itself has been off the loop since
the wake-up wait moved to the tick.
No change in behaviour otherwise: the link, receive and console paths
stay where they were. SWTGW218AS: code +45 B, xdata +1 B, stack
unchanged.
The health checkpoints follow the work they measure: the seconds block,
SFP, TX and STP phases are taken inside handle_tick(), the link, RX and
command phases in idle().
The link-change interrupt was set up at boot (mode 0x5f84, mask 0x5f34)
but never enabled: the handler did nothing and did not clear the event in
the switch, so EX0 stayed commented out and idle() read the two link
registers on every pass instead, 400 reads a second on a quiet switch.
The handler now only latches a flag and masks itself; the register access
macros build a write in the shared SFR data bytes, so an interrupt that
touched the switch in the middle of a write from the main loop would
corrupt it. idle() clears the event register (write-one-to-clear, 0x3ff
for the ten ports), re-enables EX0 and then reads the link state, in that
order, so a change that lands during the read raises a new edge. The flag
is also set once a second from the seconds block, so a board whose INT0
line turns out not to be wired keeps detecting link changes, a second
late at worst. Boot drops the events pending from bringing the links up
before the mask is set.
Measured on an RTL8373 switch before this change: 0x5f88 held 0x3fd, nine
ports had reported a change nobody read. With the change a counter in the
loop went 2 -> 3 -> 4 on "port 5 off" / "port 5 on" and stayed at 4 over
three reads without events, so the event is delivered, cleared and
re-armed, and there is no flood.
SWTGW218AS: code +57 B, xdata 0, stack 151 -> 150 B; the flag is a bit
variable. The handler compiles to clr EX0 / setb link_irq / reti.
idle() also keeps in a bit what it saw in NIC_RX_BUFF_DATA when deciding
whether to sleep, and the first iteration of the receive loop uses it
instead of reading the register again a moment later. Between the two
only the link check and handle_sfp() run, and neither can make a queued
packet disappear. Every later iteration reads the register as before, so
the budget loop behaves as it did. This part was not measured on
hardware: one register read per pass needs a throughput run to show up.
SWTGW218AS: BANK1 and BANK2 +6 bytes each, BANK3 unchanged.
stp_timers() ran every fourth pass of the main loop and stp_clock counted
passes, which only measures time while a pass is one tick long. It never
quite was: a pass is as long as the packets it handles, and #482 now takes
up to four of them, so under an IPv4 stream a pass is about 16 ms and STP
time runs at a third of its rate, with hellos 6 s apart and a root aged out
after a minute. Since #483 the loop also stops sleeping while packets wait,
so under a flood of cheap frames passes come faster than ticks and STP time
runs fast instead, shortening the forward delay in exactly the situation a
loop produces. uip_periodic() had the same problem from the other side: it
ran once per pass, so the retransmit timer sped up with the loop.
Both now go by the tick counter the timer interrupt keeps. The STP block
catches up on ticks a long pass missed, at most eight steps at a time, and
handle_tx() runs its periodics once per tick at most. One byte of xdata
more, 48 bytes of code.
A host test drives the gate with one pass every 5 ms, every 16 ms and
every 0.6 ms for ten seconds each; the STP clock lands on 500 steps in
all three, where counting passes gave 156 and 4166. A pass of 1.3 s loses
time rather than firing 65 steps at once, and the arithmetic survives the
tick counter wrapping.
The counters, the phase hooks in idle() and the "health" command are now
behind HEALTH, set from the command line with HEALTH=1. Without it the
hooks are empty macros and the command does not exist, so a default build
carries none of it: on SWTGW218AS that is 1065 bytes of bank 2, 101 of the
common segment and 28 of xdata, plus seven banked calls per main-loop pass.
It is a developer's tool. Reading the dump takes knowing the main loop, and
a user who needs it for a report can build with the flag on, which is how
the kernel treats its lock and latency instrumentation as well.
Every probe of a misbehaving switch so far measured it from the
outside. This puts the witnesses inside.
Each idle() pass increments a loop counter and stamps a checkpoint
after every phase: link polling, SFP, RX, TX, STP and the command
dispatch. A phase spanning two or more system ticks counts as slow and
its worst time is kept, in 5 ms units. handle_rx counts frames, so the
dump separates a flooded CPU from a stalled loop.
At boot the free stack area is painted, preserving the interrupt state
around the painting, and the dump reports how much of the pattern
survives next to the live stack pointer. The TCP connection table is
printed whole: state, timers, retransmissions, ports and peer, next to
the httpd transfer state, so a permanently occupied slot names its
occupant. With more than one slot configured every slot is listed.
Everything is raw hex; two dumps a known time apart give the rates.
The implementation sits in cmd_parser next to the other command
handlers and needs no storage beyond its counters.
Building with SDCC 4.6.0 emits tons of warnings e.g.:
cmd_parser.c:31: warning 356: object in read-only code space should be const
cmd_parser.c:36: warning 357: pointer to object in read-only code space should be pointer to const
These of course become fatal when building with --Werror.
Comparing resultant binaries, it seems that a single string is shifted
(deduplication?) but the numbers emitted at the end of the build are
otherwise identical.
idle() went to sleep before it looked at the receive buffer, so a packet that
arrived just after the loop dozed off waited for the next tick before anything
touched it. Every TCP round-trip paid that toll, which is why the web UI felt
sluggish even though no phase of the loop was anywhere near busy.
Check the receive buffer first and only sleep when it is empty. The read takes
its result straight from SFR_DATA_U16 rather than going through reg_read_m()
and the sfr_data[] copy, which is what the rest of the tree already does.
Measured on SWTGW218AS with this change alone:
web UI, median of 15 requests for the main page 88 ms -> 76 ms
CPU port under a one-way UDP stream 159 -> 230 packets/s
The loop still sleeps normally when there is nothing to do, so this does not
turn the core into a busy-wait: loops/ticks stays at 0.99 on an idle switch,
and rises above 1.0 only while packets are actually queued.
Costs 12 bytes of code and no extra XDATA.
handle_rx() picked up exactly one packet per iteration of the main loop. Since
the loop sleeps until the next tick, that capped the CPU port at roughly one
packet per tick no matter how little work it had to do. A burst of broadcast,
ARP or IGMP traffic aimed at the CPU queued up behind that and pushed out the
STP and LACP timers.
Drain up to RX_BUDGET packets in one pass instead. The budget matters: without
one a sustained flood would spin here and starve everything else in the loop.
The two register reads in the loop take their result straight from
SFR_DATA_U16 rather than going through reg_read_m() and the sfr_data[] copy,
which is what the rest of the tree already does.
Measured on SWTGW218AS with a one-way UDP stream, counting the packets the CPU
actually processed, with this change alone:
before 159 packets/s
RX_BUDGET 4 245 packets/s, loop iteration ~16 ms
RX_BUDGET 8 298 packets/s, loop iteration ~26 ms
Throughput is already most of the way there at 4, so the larger budget mostly
buys a longer worst-case delay for the other phases. STP stayed responsive in
both cases.
Costs 71 bytes of code and no extra XDATA.
boot.c calls it from BANK3 and only rtlplayground.c had a prototype, so
the compiler saw an implicit declaration. The call itself was fine, the
function lives in the common area, but the warning was real. Move the
prototype into the shared header.
Reported by vDorst.
sfp.c takes handle_sfp, sfp_module_read, sfp_apply_quirks, sfp_get_info,
sfp_read_field, sfp_print_info, setup_sfp_gpio, the quirk table and the module
state that goes with them. Everything exported is __banked: handle_sfp() and
sfp_print_info() are reached from cmd_parser.c in BANK2, the rest from the
common area, and both are bank boundaries.
The quirk table needed checking rather than assuming. Its entries are __code
pointers, and a __code pointer carries no bank, so passing one to a function in
a different bank hands it an offset read through the wrong window. That is safe
here because strcmp() sits in the common segment at 0x51f and is reached with a
plain lcall, so the bank register still says 3 while it runs. Verified in the
built image: the table at 0x35580 holds 0x563c and 0x5644, which resolve to
"QSFPTEK" and "QT-SFP+-T" inside BANK3.
Common segment 13393 -> 8432 bytes, leaving 7492 free rather than 2531. BANK3
holds 5710, BANK1 is unchanged and BANK2 grows by 31 for the trampolines.
All 34 machines in machine.h build and link, and the same walk over the
generated assembly finds no plain lcall crossing a bank boundary.
The common segment is the scarce one: sixteen kilobytes shared by every bank,
and before this it had about 2.5 kB left. Most of what moves here runs once at
startup and does not have to sit in it. The two SerDes helpers are the
exception: the link-change handler and the SFP polling both reach sds_config()
while the switch is running, so they are not startup-only. None of it is
reached from an interrupt.
boot.c takes setup_i2c, init_smi, nic_setup, rtl8373_revision, rtl8224_enable,
early_boot_handle_button, set_hostname_default and the two SerDes helpers.
BANK3 is enabled with the linker flag; nothing else in the build needed
changing.
Everything moved is declared __banked, since every caller is outside BANK3:
main() and friends run from the common area and rtl837x_init.c calls
sds_config() and sds_config_mac() from BANK2. The calls the moved code makes
outward were already banked, so that side needed no work.
Common segment 13393 -> 10137 bytes, leaving 5787 free rather than 2531.
BANK3 holds 3732. All 34 machines in machine.h build and link. Walking
the generated assembly for plain lcalls that cross a bank boundary finds none
among 2808 calls; those build cleanly and only fail at run time, so it seemed
worth checking by machine rather than by eye.
The lookup tables live in BANK1, so the routine switches the code bank to
reach them with movc and never switches it back. That is the contract the
__naked declaration already implied: same bank or common segment only.
The name now says it.
crc16_bank1 is the routine unchanged. crc16 becomes a __banked wrapper in
BANK1, so a caller from another bank has its own bank put back by
__sdcc_banked_ret. The two existing call sites take the direct path and
pay nothing.
isr_ext2() ends with PCON |= 1, putting the core to sleep from inside an
interrupt handler.
The DW8051 leaves idle when any enabled interrupt is activated, so the core
does not stay down for long. It naps until the next enabled interrupt request
turns up, with the 200 Hz system tick putting a ceiling of 5 ms on that, and
then carries on.
The sleep buys nothing either way, because the instruction after it is the
return. While it lasts the handler holds the priority latch, so everything at
its level or below waits, and that includes the tick, the console and the NIC
receive interrupt.
The handler still clears its flag, which is what it has to do. The bit numbers
beside the two masks were wrong: 0xef clears bit 4 and 0xdf clears bit 5,
not 7 and 6.
isr_ext2() ends with PCON |= 1, putting the core to sleep from inside an
interrupt handler.
The DW8051 leaves idle when any enabled interrupt is activated, so the core
does not stay down for long. It naps until the next enabled interrupt request
turns up, with the 200 Hz system tick putting a ceiling of 5 ms on that, and
then carries on.
The sleep buys nothing either way, because the instruction after it is the
return. While it lasts the handler holds the priority latch, so everything at
its level or below waits, and that includes the tick, the console and the NIC
receive interrupt.
The handler still clears its flag, which is what it has to do. The two wrong
comments next to the masks go as well: 0xef clears bit 4 and 0xdf clears bit 5,
not 7 and 6, and the masks already say that without help.
Add a `mac <aa:bb:cc:dd:ee:ff>` console command (and a bare `mac` to show
the current address) that overrides the management MAC at runtime. The
address is validated (unicast, globally administered, non-zero OUI) and
the static L2 management entry is re-registered so the change applies
without a reboot. Because it is a normal command, a line in the startup
config persists it across boots: execute_config() runs it before the final
static L2 entry and the derived hostname are set up.
Also point the keepLink KP-9000-9XHML-X V3.1 machine definition at the
factory MAC area (0x1FC000, same location other machines use) so a valid
factory MAC is picked up at boot instead of falling back to a locally
administered address.
The MAC parsing/printing lives in parse_mac()/print_mac() helpers next to
parse_ip()/print_ip() so future commands can reuse them, and a memcmp()
helper joins the project's own memcpy()/memset() (no libc is linked).
isr_ext2() ends with PCON |= 1. On the DW8051 any enabled interrupt request
ends idle, so the handler sleeps until the next request arrives, the system
tick at the latest, and only then returns. Everything at the same priority
waits with it, and the instruction after the idle is RETI, so the sleep buys
nothing.
The handler still clears its flag, which is what it has to do. The other four
uses of PCON |= 1 are in task context and are left alone.
uip_arp_ipin() is an empty macro with its body under #if 0, both inherited
from the uIP import and untouched since. That leaves uip_arp_update()
reachable only from uip_arp_arpin(), so an entry is refreshed only by ARP
addressed to us and ages out after UIP_ARP_MAXAGE no matter how much traffic
passed over it.
When it goes, the next transmission to that host hits the miss path of
uip_arp_out(), which overwrites the packet in uip_buf with an ARP request and
returns. For TCP that costs a retransmission. For UDP nothing retransmits, and
handle_tx() sends the UDP connections through uip_arp_out() too, so the
datagram is lost.
The body could not be enabled as written: uip_len -= sizeof(struct uip_eth_hdr)
is a leftover from when UIP_LLH_LEN was 0. Here it is ETHER_HEADER_SIZE +
RTL_FRAME_DESC_SIZE and uip.c reads the IP header at uip_buf[UIP_LLH_LEN], so
uip_len has to keep the link layer in it. The rest of the function is sound.
write_char() masked writeptr and never looked at readptr, so once more
than LOGBUF_SIZE bytes were written between two drains the ring wrapped
over content that had not been sent yet.
That is not a corner case. The ring is emptied once per main loop pass,
while a single command runs to completion inside one pass, and a full L2
listing prints well over twice the 512 byte buffer. On hardware the whole
1227 byte dump came out as one 174 byte datagram whose first line began in
the middle of a MAC address.
Drop the character when the ring is full instead of overwriting, so what
has been logged stays intact and it is the tail that is lost. A full ring
also flags a line, otherwise a burst without a newline would leave the
reader waiting on line_available forever and syslog would stop for good.
The EX0..EX3 handlers each emitted a single debug character through
write_char(), which busy-waits on the serial TX-empty flag that is set by
the serial interrupt. If one of these handlers runs while a byte is being
transmitted, it waits for a flag that the equal-or-lower-priority serial
interrupt cannot deliver, hanging the handler with the system tick stopped.
The characters were only ever debug markers, so drop them; the handlers now
just acknowledge the interrupt. No interrupt service routine should call the
blocking console path.
uip_arp_timer() was defined but never called, so ARP entries were only
refreshed on new learning and only removed under table pressure. A cached
entry for a peer whose MAC later changes (a gateway failover, a replaced
device) is then used until it is evicted, and traffic to anything reached
through it is sent to the old MAC and lost, while on-link traffic is
unaffected.
uIP expects the timer roughly every ten seconds; drive it from the
once-per-second housekeeping in idle().
The CPU's own MAC exists in the L2 table only as a learned entry,
created whenever the CPU transmits, and it ages out like any other
dynamic entry. Unknown unicast is not flooded to the CPU port, so on an
idle switch (no web session, no management traffic) the entry expires
after the aging time and frames for the management IP no longer reach
the CPU: pings die until the next CPU transmission (an ARP reply)
re-teaches the entry, then die again. Real management sessions keep the
entry alive continuously, which is why this is only visible on idle
switches.
Install a static entry for the management MAC on the CPU port after the
startup config has been replayed, so it lands in the final management
VLAN, and move it when the management VLAN is changed at runtime.
Entry mechanics, established on hardware: a table write with read-method
0 hashes the key in TBL_DATA_IN and places the entry itself (a search
returns index 0 on a miss, there is no software-visible insertion slot).
The age field in the third data word must be non-zero for the entry to
be visible to lookup at all, and the static flag (bit 0 of byte 1 of
that word) stops the aging engine from decrementing it: with the flag a
full-age entry survives untouched where an identical unflagged entry
ages to invisible within the aging period. With no management VLAN
configured the entry lives in VLAN 1.
Three ways the answer could mislead the caller, all in the paths that
matter most when something is wrong.
The capture sat in write_char(), so anything printed through
print_string_no_syslog() escaped it. That is exactly the replies of the
syslog commands, which deliberately avoid the syslog path: "syslog on"
answered with the bare address and no sentence around it, "syslog off"
answered with nothing at all. Moving the capture one level down, into
write_char_no_syslog(), catches both paths and costs nothing, since
write_char() reaches it anyway.
On a parse error send_bad_request() rewrote the buffer from the start,
throwing away the very text that explains the error and replacing it
with the 400 HTML page. Keeping the captured text and restating only the
status keeps the parser's own message; "400 NO" is as long as "200 OK",
so the header does not have to be rebuilt.
An overlong listing was cut at the buffer end with nothing to show for
it, so a clipped answer read as a short one. It now ends in a marker,
and the reserved room is accounted for in the guard.
While here: a command that configures something prints nothing, and an
empty body reads the same as "nothing ran", so a successful silent
command now answers "OK".
No internal RAM and no xdata; 174 bytes of BANK1, which has 7356 left.
POST /cmd runs the command and answers with an empty 200, so a caller cannot
tell "done" from "nothing happened", and whatever the command prints only
reaches the serial console. Reading a register over the network needs a second
channel just to see the answer.
write_char() is the one funnel every console helper goes through, and it already
tees into the syslog buffer. A third sink, live only while the httpd runs a
command that arrived over the network, puts the same bytes into the response
behind the header. Serial and syslog keep getting their copy.
The capture stops at the end of the response buffer, so a long listing is
truncated rather than overrunning it.
BANK1 grows 39 bytes and the common area 52. One byte of xdata, BANK2 unchanged.
stp_enabled is a flag, so say bool. cmpBytes() returns a comparison
result, so say int8_t. The three busy waits this branch adds read the
status straight out of the SFR instead of copying four bytes to xdata
first.
tcpip_output() decides whether to splice in the 802.1Q tag, and that
decision also moves the frame: the header is shifted forward over its
padding, so a tagged frame starts at uip_buf with the q_frame layout,
while an untagged one keeps the padding and the nonq_frame layout.
nic_tx_packet() took that decision a second time, from management_vlan
alone. That agreed while the sender suppressed the management VLAN around
the transmission, but not since the tag is skipped per frame for a
CPU-tagged one: the descriptor then still sits behind the padding while
the transfer is set up for the shifted layout. The frame goes out four
bytes early and its length is read from the offset where tx_seq and
chksum_flags live, so a sixty byte BPDU is sent as around 1800 bytes of
whatever follows it. Looped back it is no longer a BPDU, the port hears
nothing, auto edge promotes it and the loop stays open.
Record the decision where it is taken and let the transfer follow it.
A variable rather than an argument because internal RAM is full once the
aggregation module shares the image: the overlay area ends at 0x7f, and
an argument or any temporary for the condition no longer fits.
The port was frozen at 514 in the call that opens the connection, so a
collector listening anywhere else was simply out of reach, and plenty do,
because 514 is privileged and containerised collectors usually get a high
port instead. Working around it meant putting a proxy in front, which then
rewrites the source address and hides which device actually sent the line.
Add `syslog port <n>`. The default stays 514, so nothing changes for an
existing configuration. Setting it tears the connection down and builds a
new one, the same dance the address already does, because uip_udp_new()
freezes the port into the connection.
The value is parsed here rather than through atoi_short(), which reports
"no digits" but not overflow: 65540 would quietly wrap to 4 and we would
open a connection to a port nobody asked for. Checking before each multiply
keeps it in 16-bit arithmetic. Zero then covers all three ways to be wrong -
no digits, past 65535, or an explicit "0", which is not a port either.
Whitelist the new command in config.js as well, next to `syslog ip`, or the
line is dropped without a word when the configuration is saved and the
setting quietly fails to survive a reboot. The dedup entry has to precede
the general `^syslog\b` one, otherwise it would deduplicate against
`syslog on`.
itoa_short() is new: itoa() only handles a byte and print_short() prints
hex, so there was no way to show a port as a decimal number. Kept separate
from itoa() rather than widening it, because every existing caller passes a
byte and would start paying for 16-bit divisions it does not need.
The scratch variables for the parser live in xdata. Locals there would take
internal RAM, and this image has none left: data ends at 0x77, the overlay
occupies 0x78-0x7f and the stack starts at 0x80. Measured: no module's DSEG
grew.
Both conflicts are the register keyword removal meeting a change of ours,
so each takes main's signature and keeps what the branch was saying:
nic_rx_packet() still returns a bool, and port_ingress_filter_get() stays
declared.
main has since put its own copy of the STP module in BANK2, so the pragma
this branch carried is now duplicated. The one with main's comment stays.