Difference between revisions of "WiFi"
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Revision as of 16:54, 9 November 2013
TI Wl1251 802.11 b / g and e / i / d / k
A suggestion for improving connection speed is to disable power-saving
sudo iwconfig wlan0 power off
Depending on the situation, this may help. detailed report, which concludes, that disabling power saving very likely improves the situation (on the Original, Rebirth and the 1Ghz Pandora), as of 2013-01 SuperZaxxon 1.52, the power saving algorithm in the binary blob from TI and/or its calibration is so over-aggressive, that it fails in many situations.
Terminal wifi configuration
Sometimes, you may wish to bypass network manager and configure the wifi directly. See Wireless from the Terminal for some guidance on how to do this.
Android HotSpot Tethering
Android phones running 2.2 and above provide the option to share a mobile network connection using WiFi. This is tested for connecting to the Pandora and works (at least with a HTC Desire).
ED buys wifi chips that are supposed to be pre-calibrated in factory (calibration data stored in an EEPROM inside of chip), but it is known that unlike pandora, other devices like N900 and HTC Dream did calibration only after full assembly, so chip-only calibration might be wrong. We don't have any hardware/software tools for automatic calibration, so since SuperZaxxon 1.54 there is an ability to dump calibration NVS/EEPROM for manual hex editing, and to load it into the chip from file instead of EEPROM (one time only, not permmament).
Dumping the calibration (NVS)
Basic linux terminal console skills are required for this operation. First make sure wifi driver is unloaded:
$ sudo rmmod wl1251_sdio
Now load the driver with special argument:
$ sudo modprobe wl1251_sdio dump_eeprom=1
The driver will now take ~20s to load, as it will dump NVS on startup. When the command is done, check dmesg output for "wl1251: eeprom dumped." to see if dumping was successful:
$ dmesg | tail ... [ 7727.834442] wl1251: using dedicated interrupt line [ 7743.942993] wl1251: eeprom dumped. ...
Now you need to to get the dump out of the driver to a file, which is done through debugfs:
$ sudo mkdir /debug $ sudo mount -t debugfs debugfs /debug $ sudo cp /debug/wl1251/dump_nvs /somewhere/wl1251-nvs.bin
You should now have NVS dump in /somewhere/wl1251-nvs.bin
Dump file format
See http://notaz.gp2x.de/misc/pnd/wl1251/nvs_map.txt for wl1251-nvs.bin format description that has been found somewhere on the net.
Loading calibration from file
Loading a NVS file instructs the chip not to read the EEPROM, driver uploads the data to chip instead, so doing it doesn't make permament changes. First we need to unload the driver again:
$ sudo rmmod wl1251_sdio
Copy the (possibly modified) file to /lib/firmware/
$ sudo cp /somewhere/wl1251-nvs.bin /lib/firmware/
Now load the driver again with special argument:
$ sudo modprobe wl1251_sdio force_nvs_file=1
Wifi should now start with calibration from file. Note that this mode doesn't set up your usual MAC address, it will be random.