Sunday, November 22, 2009

Additional instrumentation in a BMW Bavaria

I find having a few more instruments occasionally useful but I don't want to hack up my dash for additional analog gauges and, in the yellow Bavaria, the AC center console doesn't leave much room for extras anyhow.  The Bavaria was designed at a time when smoking seemed to be a critical car interior feature, but I don't smoke.

Here's a graphical VFD screen (from Noritake) that I found while cleaning out some boxes at home and lined it up on a spare interior vent / ash tray panel.   It's controlled by a fairly simple and documented interface and VFDs are great in cars: they're easy to read in virtually all types of light and they work well through a large temperature range.  They also have a cool vintage look to them, they're what you often see on a high-end stereo.

I'm thinking of hacking up a quick MCU-based control board and reading some basic sensors along with a battery meter.  A button or two should suffice to toggle between readings and the MCU could even chose to show a particular reading and make an alarm when that value is critical (ex: low oil pressure), just like it's done on some new cars.

This particular module is about the right size for the ashtray cover area, it would just need a nice wooden bezel done with a matching veneer for the "roots" trim I have here.

Monday, September 28, 2009

5-speed transmission road trip

Alright, I am back home in San Francisco.  The 5-speed transmission swap went absolutely smoothly and I made it back in record time.  Just kidding.

I definitely had a plan and alotted a significant amount of time but the project nearly wound up a disaster.  In fact, it would have been if it wasn't for the huge amount of help and support from my good friends Jason, Mira, Eric, Seth, and Brant.

The basic idea was to fly up to Jason and Mira's house in southern WA state and replace the broken automatic in my Bavaria with a rebuilt Getrag 265 5-speed gearbox, using a mix of mostly new factory parts and an occasional used item as needed.  My friend Brant would then fly up later in the week and buy Jason's 1969 2500.  We would then leave on Saturday or Sunday and caravan together to San Francisco (and, in his case, Santa Cruz).  The 2500 runs well but its cooling system was weak and the car had some wiring problems that we wanted to address before the drive home.

The transmission swap took a lot longer than I thought: removing the automatic took up almost an entire day, the horrible thing was really stuck in there and we used all maner of creative hacking to finally free it from the car.  I then installed the flywheel and found that the clutch pressure plate doesn't fit.  I had accidentally been sent a flywheel for an M20 motor, which has a 1/4" smaller diameter for the pressure plate.  Having figured that out, I bought a proper M30 flywheel from Jason and we continued with the install, but this put us into late Friday night for the driveshaft installation.  At this point we realized that the guibo (drivesahft-to-gearbox coupling) that Jason has for me was already installed on Brant's car two months ago when I was up there -- we both had forgotten about that.  It's not really possible to get one of those on a Friday night or a Saturday, but we found a BMW dealer that at least had the E28 5-series version of the part in stock and for sale on Saturday morning.  The part, however, didn't match the drawing in the parts book and therefore was a bit too short for the drive shaft that I had.  We hacked around for a while and Jason finally came up with a very clever way to adapt it.  Finally, with the driveshaft installed and with Seth and Eric's help, we buttoned up the car and were ready to test-drive it.  Seth and Eric also addressed the cooling problems on Brant's car by adjusting the belt tension and upgrading its magnetic fan clutch and five-blade fan to the more modern viscous coupling design with an E12 fan.

It was late on Saturday night, the day before the long trip home, that I finally put the car in reverse, pulled it out of the shop, and really drove it for the first time with the new gearbox.  Everything seemed to work great, so I got in the back and gave Jason and Brant a turn at the wheel.  We heard a weird noise followed by a few scrapes and the car started stumbling and then promptly overheated.  We limped back to the shop and popped the hood to find that a metal support piece that ran vertically up the radiator in the very front had somehow detatched and caught up in the fan.  The radiator was leaking due to a gash from the piece of metal, the fan blades were broken, and one of the plug wires was broken off at the distributor cap.

We worked late into the night to replace the damaged radiator with a decent spare from another Bavaria for the trip home.  We also installed one of Jason's spare fans and replaced the damaged plug wire set.  The car was finally buttoned back up with the cooling system bled at quite a bit past midnight and test-drove rather well.

Brant and I started off on Sunday morning for the long trip back home.  We fueled up, merged onto highway 5 South toward Portland, and kept an eye on our respective coolant temperature instruments.  I heard a stange noise somewhere near Vancouver, WA and then Brant swerved to avoid my radiator fan and fan clutch assembly, which had been thrown from the car.  We pulled off the highway into a gas station parking lot and I popped the hood to inspect the damage.  The fan clutch was indeed missing but, this time, there was no damage to the radiator or wiring.

Jason suggested an electric puller fan strapped to the radiator to cool the car for the trip down and looked up a nearby Schuck's auto parts store to visit.  Brant and I walked in the moment they opened and a helpful employee found us a suitable fan, helped us test-fit it by looking at Brant's car, and made sure that I remembered to at least buy a toggle switch to wire it.  Brant and I removed the remaining fan clutch mounting hardware to maximize clearance and then installed the electric fan which I wired straight to the battery via the toggle switch.  It worked amazingly well: the car ran nice and cool at city and highway speeds, we were back on the road.

We proceeded South after a breakfast and coffee stop in Portland (we randomly chose Blitz's in the Pearl District, I highly recommended it).  The weather warmed up and Brant's car started overheating but we carefully pressed on.  Both engines started running hotter as we got in to Medford so we decided to stop and wait until dark when the weather would cool down again.  This left us with nothing much to do beside finding the nearest Irish pub and eating dinner and having a few beers.  Shenanigan's in Medford fit the bill nicely, in fact it's a really cool place and I'll definitely be back next time I pass through Medford.

We continued on our way to Califronia after the sun set.  The cars ran without much trouble once the weather cooled down and we cleared the Siskiyou mountain pass and continued through the Shasta area.  Brant's car still ran a bit warm so we took it easy through highways 5 and 505 and finally wound up in San Francisco early on Monday morning.  Brant continued to Santa Cruz later in the morning and made it home fine, I parked my car and took the bus to work in the afternoon.

There's still quite a lot to fix on this car, including an exhaust leak I caused by breaking a stud on the rear downpipe.  I still need to pass the DMV brake and lights inspection to get license plates.  It's running and driving well though and the five-speed manual works great.  This has been a horribly stressful experience overall, especially the journey home which was "suboptimal" to say the least.  I'm really thankful for the help and support of my E3 friends!

Friday, September 18, 2009

Early BMW E3 (2500 and 2800) wiring

I'm helping with some wiring repair on a friend's very early BMW E3, a 1969 2500.


The wiring on these is a bit different than on the later ('71 and on and '73 and on) cars and here's the fuse box layout. The fuses are numbered one through ten, left to right:

Parking light and tail light, left; engine compartment
License plate, luggage compartment; instruments illumination
Parking light and tail light, right
Clock; interior light
Lighter, power antenna
Windshield wiper and washer
Stoplight, horn, back-up light, turn signal, auto choke, warning lights (man. choke, fuel, oil pressure), fuel and water temperature gauge; electrical fuel pump
Back window heating, air conditioner
Heater blower
Power sliding roof, other electrical accessories

5A fuses are amber (yellow), 8A fuses are white, and 16A fuses are red. The fuse 7 circuit has quite a lot of components on it and when that blows you'll lose pretty much the entire instrument cluster.


Note that there are no headlight circuit fuses, this came later with the two-row fuse box. I suggested adding in-line fuses for the headlight circuits. I also recommend adding relays for the lights if your car doesn't have them (one for the low beams and one for the high beams) in order to reduce the current flowing through the headlight switch. This was also done on later cars, although it seems to not have happened until the 1973 model year.

Ignition Switch

There seem to be three ignition switch parts for the USA-market E3. The very early cars like this 2500 have a unique ignition switch style that is not interchangeable with the later styles (that is, they don't fit each others' lock cylinders). The part number for this early switch is 61-31-1-352-236 and the part is no longer available from BMW. The part number for the slightly later style (used until 04/1971 production, likely '72 model year) is 61-32-1-350-532 and the part is available. The later switches have slightly different wiring tails, including an additional key position, but they can be spliced into an older-style harness with the additional key position left off.

Replacing the early ignition switch

It's possible to replace the very early version of the ignition switch with one of the later switches, however that involves also replacing the lock assembly and changing some wiring.  The early ignition switch is connected as follows:
  • 12+ from the battery (red) is common to the switch.
  • small gray wire with a plug connector powers the turn signal switch.  This is not a specific switch position but is used for the hazard flasher and side market circuits, along with the turn signal itself.
  • heavy green wire connects to fuse 7 on the fuse box.  This powers the accessories and provides the "run" or "on" position.
  • black wire powers the starter solenoid, the "start" position.
There is no "accessory" position, but that came on the later cars.

Replacing the turn signal stalk

The early turn signal stalk is functionally identical to the later pre-74 stalk but wiring connector is different.  You should try to find the very early type what will plug right in or splice the later type into the early harness.  The very early cars use a rectangular plug with rectangular female connectors inside, the later cars use a square plug with round male pins inside.

The turn signal moved to the left side on the 1974 model year and is that one is a quite different design.

Friday, September 11, 2009

Transmission replacement: a plan of attack

I bought a lovely 1973 BMW Bavaria from the pick-n-pull junkyard a few months back.  The car unfortunately had a barely-working Borg Warner automatic transmission but otherwise is in great shape and I love the color.  I bought the Bavaria with the intention of replacing the automatic with a manual gearbox as soon as possible and my friend Jason in WA state happened to have a spare.  He also happened to be hosting a BMW Bavaria meet-up, WestFest 2009 at his house, so it made sense to pack some bags and head up there on a little road trip.

As bad as the transmission was, I thought I'd make it, especially after giving it a quick servicing and fluid change.  The oil pan was filled with metal shavings and the filter looked disgusting.  The oil that drained out didn't look like ATF.  Still, I changed the parts out, cleaned it up, and put it back together with new ATF.  It worked pretty well for a while, though reverse was a bit spotty up slight hills.  We made it to Jason's just fine and even took it on a group drive up the back of Mt. St. Helen.  Finally, on the way back to Jason's, we headed up a very steep hill and, half a mile from his house, the transmission stopped putting power to the driveshaft.  Oops.

On a positive note, the car is now at Jason's house and we have that spare Getrag 5-speed manual transmission, a lift, and lots of tools and fluids ready to go.  I'm headed up there in a week to swap in the manual gearbox and then drive the car home to San Francisco.  Here's an approximate check list of what's needed to convert an automatic Bavaria to a 5-speed:

  • Getrag 265 5-speed manual gearbox and bel housing.  This typically comes out of a 1980 or 1981 528i but there are other options.  However most of the associated parts (shifter, crossmember, etc) will need to be from an E12 528i, even if your transmission is from another model.
  • The transmission crossmember and mount.  This is used to hold the transmission in the car and it has to be out of a 1981 528i 5-speed.  It's not an expensive part new, so if you can't find a used one, order a new one along with a new mount.
  • The shifter.  Namely you need the shift tower (the big black metal piece), two new shift tower bushings (they're little blocks that hold the tower to the gearbox), the shifter, and the shifter linkage rod and associated clips and bushings, and an insulation pad.  You also need the shit tower rear mount, which is called a "Christmas tree" due to its shape.  It needs two metal brackets and you'll drill a hole in the tunnel for one of them to mount.  These diagrams make it clear.  Make sure you really have all this stuff, the shifter doesn't really work without it.
  • A clutch kit (or the entire set of clutch parts from the donor car).  This is typically the clutch disc, pressure plate, throw-out (release) bearing, and a pilot bearing.  Buy the new-style one-piece (sealed) bearing.  You also need the clutch fork and pivot piece.
  • A clutch slave cylinder: the 1981 528i one will work fine.
  • A clutch master cylinder: the 1981 528i one will work fine.  The mounting point for it already exists, it's where the automatic harness runs through the firewall.
  • A manual transmission car's brake fluid reservoir (it's the same as the automatic one except that there's a third line for the clutch, they're available brand new for about $20) along with some hydraulic lines.  I recommend calling Jim or Spence at Mesa Performance for the lines as they can send you the correct length of hard and flexible line to use.
  • A flywheel from a manual-transmission M30 engine.  You want the earlier (pre-E34 5-series) single-mass type.
  • A set of bel housing bolts for the 5-speed as described in the parts book.  The automatic bel housing has different bolts so you need to buy the right ones unless you have the ones from your donor car.
  • A set of pedals from a manual-transmission Bavaria: the brake pedal, clutch pedal, and the bushings and springs inside them.  These may be hard to find!  You also want the "fit bolt" and bushings shown here, they're used to connect the clutch master cylinder to the clutch pedal.  In addition, get the clutch pedal return spring if you can.
  • A flex disc (or 'guibo') of the automatic style rather than the kind found on the manual cars.  You'll then be able to reuse the driveshaft bolts from your car, and this kind of link is more durable.  The part number is 26 11 1 209 168 or 26 11 7 511 454. 
  • You should also buy a rear main seal and change that out while you're in there, unless you're sure yours is fine.
  • I recommend buying a new reverse light switch for the transmission just in case the one already in it is bad, it's a very inexpensive part.  You'll need the reverse light switch harness from a manual car, or you can make your own.
  • The manual transmission style center console shifter part for the Bavaria.
  • A manual transmission Bavaria or E12 (530i or 528i) radiator would be nice, but not required.
That should about cover it, I hope.  I sort of cheated because my friend Crow and I recently did the same conversion on his 1973 Bavaria so I got to experience it first-hand and refresh my memory on some details.  Craig Dinger has a very good auto-to-manual writeup with pictures and notes about the wiring changes required for 1974 and later cars.  I recommend having that handy.  The SSR site also has step-by-step instructions for the conversion to a 4-speed along with wiring instructions for 1973 and earlier cars.

On a side note: the automatic transmission is a bit longer than the Getrag 4-speed that should have come with the car.  The Getrag 5-speed, however, is about the same length as the automatic.  This means that the automatic car's drive shaft and speedometer cable line up with the 5-speed but not the 4-speed (the speedometer cable is too long and the drive shaft is too short).   I recommend replacing your automatic with the 5-speed unless you've found a 4-speed E3 parts car with everything you need.

draft-802.11s mesh status: 2.6.31 and 2.6.32

Here's a quick Linux draft-802.11s mesh status update:


The 2.6.31 kernel has been released and it unfortunately ships with mesh temporarily disabled. To enable it, edit net/mac80211/Kconfig and remove the depends on BROKEN line under the config MAC80211_MESH section, then configure your kernel.  The problem that lead to mesh being marked broken has been resolved by this patch, which should be in 2.6.32.


A number of issues have been addressed for 2.6.32, including roll-ups to the current 802.11s draft.  For example, we now use the 3-address format for broadcast frames (patch) to work around a problem with some WDS-capable access points already on the market.  The mesh Information Elements have been brought up to date as well (patch), this will help with interoperability with FreeBSD's draft-802.11s stack but of course breaks compatibility with Linux-based mesh nodes that do not have the Information Element patch.

The mesh stack previously relied on the (now deprecated) "PID" algorithm and, when "minstrel" replaced "PID", things broke.  The mesh air-time link metric has been restored by decoupling the failure average statistic from the Rate Control algorithm and fixing early detection of broken links for the "minstrel".  The latter will need to be addressed for drivers that implement their own RC algorithm.


At this time, I recommend testing Mesh Point mode with the b43 and ath5k drivers, however a complete driver status list can be found on the o11s wiki.  It's also possible to use ath9k and rt2x00 but they won't beacon right away.  The workaround is to issue a scan, after which you'll see mesh beacons (bugs 14187 and 13752 respectively).

The Future

Additional draft roll-up work is needed, along with finishing the Mesh Point Portal (MPP) support.  There are also a few minor driver bugs to address.

Thursday, June 25, 2009

wireless drivers that support Mesh Point mode

Here's a little script that I developed to query your Linux PC for information about mesh-capable wireless drivers, if any. It prints the relevant phy names, MAC addresses, and driver name. It just requires a recent version of iw. For example:

$ ./
phy1 00:1f:c6:20:c1:71 rt73usb
phy0 00:ff:f3:a0:24:bd ath5k

You then know what phy to use with iw (and what driver supports your device, if you're curious). Here's the script:


PHYS=`iw list | grep Wiphy | cut -d ' ' -f 2`

for phy in $PHYS; do
iw phy $phy info | grep "mesh point" >/dev/null
if [ "$?" = "0" ]; then
MAC="`cat /sys/class/ieee80211/$phy/macaddress`"
DRIVER="`ls /sys/class/ieee80211/$phy/device/driver/module/drivers/ 2>/dev/null | cut -d ':' -f 2`"

echo "$phy $MAC $DRIVER"

Thursday, June 11, 2009

Libertas GSPI driver in 2.6.30

The Libertas GSPI driver that I worked on is now mainline, as part of Linux kernel 2.6.30. While this is definitely good news, there have been subsequent improvements to the driver they'll land in upcoming kernels.

If you're planning to use this driver (which supports SPI-interfaced Marvell 88w8686 cards), please also take a look at:
  • this patch to remove the use of GPIO Chip Select in the driver. If you're using a Blackfin-based system, you'll need to configure your SPI controller to use GPIO-based Chip Select but that can be done in your board config and didn't belong in the libertas_spi driver!
  • this one with endianness fixes, especially needed for big-endian systems (ex: PowerPC)
  • this one with a fix for IEEE Power Save mode
...or, better yet, pull the driver from wireless-testing if possible so that you're working with the latest.

Wednesday, March 18, 2009

BMW repair: your charcoal canister and you

I wanted to comment on something that I keep seeing: cars where the owner or previous owner has disconnected the charcoal canister. If you haven't seen one recently, it's the little can that normally sits under the battery tray on your BMW Bavaria, 3.0CS, 2002, etc. and maybe in other places on cars like the E12 5-series. It has two lines that plug in to it. Here's one that, of course, was removed for no good reason:

The fuel tank ventilates into a small plastic expansion tank in the trunk. From this tank, there is a blue plastic tube that runs through the length of the car and into the engine bay and then into the charcoal canister. From there, a second tube runs to your air cleaner (or intake manifold on fuel-injected models), where the fuel vapor from the expansion tank is eventually burned by the engine. The charcoal in the canister serves two purposes: first, it stores the hydrocarbons from the fuel tank ventilation while the engine is not running (that is, while engine vacuum isn't pulling the vapor into the air cleaner or manifold), secondly, it is a safety mechanism: a backfire in your intake won't make it back into the fuel tank.

Now sure, after many years, the canister looks pretty nasty (mostly due to battery acid eating away at it). Replacements are readily available new (example: "activated carbon filter") and they're not that expensive. I've seen the damn thing disconnected by the previous owner of every car I've owned or helped a friend buy and there's never much of an explanation offered as to why:
  • Sometimes the owner is confused, the last one handed me the car's original Zenith carburetors in a box and in there was the canister. He asked me, "what is this thing anyway? I took it out".
  • Sometimes it's "I was taking out the smog equipment and this seemed part of it".
The canister does not decrease the performance of your car or otherwise cause you problems. It's not part of the EGR system or some other smog stuff that causes the engine to burn exhaust gases.

On the 2002 we have, as a bonus, the fuel tank vent tube was plugged with a bolt by some previous owner -- that's really bad, as pressure in the tank will then keep building up with nowhere to go.

If you're really set on the idea of taking all this stuff out, or you have nowhere to connect the line because you've converted to Weber side drafts and have no air cleaner to speak of, look at how it was done on European-market cars: they simply ran the vent line from the expansion tank down under the rear bumper, but there was still a vent line. On even earlier cars, there was no expansion tank but the fuel filler cap or neck were vented to the outside.

Please also consider this when you complain of fuel vapor inside the car. Perhaps this small set of tubing that is supposed to vent out the fuel tank into the air cleaner is no longer hooked up, venting fuel vapor into the engine bay? Or did someone disconnect the line at the expansion tank, causing vapor to leak into the trunk?

In addition, on later cars like the E12 528i and E28 five series, there is a thermal/vacuum-operated switch in-line with the tubing from the canister on its way to the intake manifold. This additional step keeps the fuel vapor from being burned before the engine is warmed up (and then is able to burn it better), which decreases emissions. This is probably overkill for early cars that never had it, but that's what it's for in case someone is wondering.

(thanks to Tony and Keith on the SSR list and to john_a on the 2002 FAQ message board for additional details).

Sunday, March 15, 2009

Vespa Ciao wiring repair

I'm doing some minor repairs on a 1976 Vespa Ciao, which is a cool little 50cc moped. I was quite happy to find out about Zippy Moped, who stock a lot of parts for the Ciao.

The wiring on this Ciao had deteriorated over the years and showed some poor-quality repairs. One of the previous owners also lost the bracket that hangs over the engine and holds the foot rest cover and, I suspect, keeps the wiring away from the hot engine casing.

Here's what I've learned about Vespa Ciao wiring so far:
  • the electrical system is 6V AC. Don't forget to put your multimeter in AC voltage mode before measuring since you normally use DC. For example, I wanted to know if the ignition feeder coil and condenser circuit were actually pulling 6V across the ignition coil so I disconnected the coil and measured the voltage (with respect to the engine casing) while pedalling.
  • electricity is generated by a magneto that consists of the flywheel, which has magnets on the inside, and two 'feeder' coils that sit underneath it. One coil is for the 'lighting' circuit (front and rear lights, horn) and the other connects to the ignition coil through a condenser. The main shaft that the flywheel spins on actuates the ignition points, which can be adjusted through a little window that's normally closed off by a rubber cover.
  • the wiring is really simple but not very robust: a burnt-out tail light can be enough to kill the ignition and putting a 12V bulb in the tail light (as was done by some previous owner) is really bad. If in doubt, unplug both brake light switches from the handle bars and, on each one, short their two leads together to bypass the tail light entirely. The correct 6V bulb is available.
  • near the engine, in general, the ignition wiring is purple and the lighting wiring is blue. There's a red wire which is the lighting circuit ground and a black wire which is the ignition circuit ground. There are several wiring diagrams available but none of them seemed to match this Ciao and that seems to be fairly normal.
  • You need a special tool to remove the flywheel, and you need to do that to get to the 'feeder' coils and condenser. It's not very expensive and you can get it from Zippy Moped Parts.
  • The clutch mechanism has two sets of shoes, one of which is only used for starting the engine. The engine should start easily with the decompression lever pressed, mine doesn't and the starting shoes do look worn. It does start when I pedal a little, so I think it needs new starting shoes.
Beside wiring repairs, I wound up installing a missing bracket and decompression cable, air filter, and fuel filter. I also replaced a broken carburetor elbow piece for the throttle cable. The Ciao now runs pretty well (and reliably) but the carburetor needs adjustment and I need to fix a fuel leak that I accidentally caused while replacing the fuel filter.

Friday, February 27, 2009

Front suspension and a little engine work on the BMW 2002

The new yellow 2002 runs and drives pretty well but the front timing cover oil leaks are pretty bad and the front suspension didn't feel too great, so we decided to do a bit of work (and take photos as we go).

On closer inspection, the motor seemed to leak pretty badly from some combination of the lower front timing cover, possibly the oil pan, and the distributor cover on the back of the head. We're not ready to rebuild the motor yet, but we figured it's worth pulling it and replacing all of the gaskets outside the car where everything is easy to reach.

Attempting to pull off the front bumper revealed that the front suspension was quite damaged. The exhaust side of the subframe was slightly twisted and bent upward at where the bumper bracket sits and the control arm on that side had a good dent in it. The bushings looked tired and we have a lot of steering play anyway, so we decided to drop the front subframe with the engine out and replace everything.

Aron found a good used front subframe that, as a bonus, came with a bigger sway bar and several good spare parts attached:

We pulled it all apart, ordered new control arms, steering links, ball joints, bushings, and other components and then Aron cleaned up the actual subframe and sent it out to get painted. We also went ahead and pulled the engine and then Aron dropped the front subframe. Here's what that looks like, after years of oil leaks:

And here's our "new" one, coming together with nice new components:

Next, we'll clean up the engine bay and replace all of the seals on the motor (along with the water pump and the timing chain and guides for good measure) and then reassemble everything.

Saturday, January 17, 2009

one more option for embedded Linux WiFi hardware

There's now one more 802.11b/g wireless chipset available to use in your next embedded Linux system. Thanks to the Blackfin folks at Analog Devices, we now have a driver for the Marvell '8686 chipset using a GSPI interface suitable for many embedded applications. We also fixed an alignment bug in the core driver so that things work on CPUs such as Blackfin and AVR32. Embedded WiFi modules with this chipset are available from several vendors. The new driver, libertas_spi, is available in wireless-testing and coming to a future kernel (2.6.30, most likely).

GSPI is very easy to interface as it consists of a normal SPI bus, an IRQ line, and one GPIO line that acts as a chip select signal (as such, be sure to enable CONFIG_GENERIC_GPIO in your kernel config in order to build the new libertas_spi driver). The GPIO-style chip select is different from a typical SPI chip select in that the chip select stays asserted for an arbitrary number of SPI bus transactions.

Wednesday, January 7, 2009

draft-802.11s mesh in the 2.6.28 kernel

The 2.6.28 kernel, released on Dec. 25th '08, brings several nice improvements to the draft-802.11s mesh support in mac80211:
  • mesh support in the ath5k driver, which supports most Atheros 802.11b/g hardware.
  • mesh parameters can now be adjusted through nl80211 via the iw user space tool instead of using debugfs.
  • initial work on MPP support -- this will allow Mesh Point interfaces to be bridged with other interfaces.
  • several bug fixes and improvements as well as some reorganization of the code.