Linux/WL1835MOD: 20 MHz MIMO

Tool/software: Linux

Hello,

  We're using a WL1835mod for our poject, with Linux and the driver maintained in its mainline. (Actually, last time I updated the driver was to commit [33e40d025ed82fcab102035db38a727c914399a4: wlcore: wl18xx: Use chip specific configuration firmware]. I don't see anything related to our proble in the subsequent commits, but there's nothing refraining me from updating again, if need be.) We're using the last firmware revision, as far as I know: 8.9.0.0.75.

  Our problem is that with wl18xx.phy.number_of_assembled_ant2_4 = 0x02 and wl18xx.ht.mode = 0x00, we only see one antenna emiting, even when forcing the bandwidth to 20 MHz on the AP side. (iw on the product confirms the 20 MHz bandwidth.) Which antenna is used is configurable with wl18xx.phy.spare0, as hinted here. But according to this other post, we should be able to see both antennas working with a 20 MHz bandwidth @2.4GHz.

  I would like to add that when using the calibrator tool, like this:

ifdown wlan0
./calibrator wlan0 plt power_mode on
./calibrator wlan0 wl18xx_plt set_tx_power 20000 0 0 11 0 $X 0 0 0 1 0 0
./calibrator wlan0 wl18xx_plt start_tx 200 19 1024 0 0 0 0 0 00:11:22:33:44:55 01:02:03:04:05:06 1

I get to emit on either antenna when setting X to 1 or 2, but 3 only emits on the default antenna (as per wl18xx.phy.spare0).

Also this: I tries using the configure-device.sh wrapper around wlconf, provided in the ti-utils-18xx repository, passing it parameters wl1835, 2 antennas, no C2CP, and obtained extacly (md5-wise) the same configuration I had tuned by hand to begin with.

Thanks in advance, Aurélien