On Sat, 2012-06-09 at 15:03 +0200, Andreas Kemnade wrote: > Hi, > > on the GTA04 (www.gta04.org) > which has a W2CBW003 chip for wifi connected to a DM3730CBP CPU. data > rates are quite low using the libertas driver from kernel 3.2-3.4 > (https://github.com/neilbrown/gta04/branches) > even near an accesspoint. That seems not depend on the encryption > settings. Rates are around 100KByte/s. iwconfig shows 5.5Mb/s if it is > not connected to an accesspoint with specially configured rates (but > still the throughput is low). > > In contrary data rates are high (>1MByte/s) with a kernel based on > the 2.6.32 BeagleBoard XM hw-validation kernel > https://github.com/goldelico/gta04-kernel > That behaviour was reported by several people. > > I tried also the libertas-tf driver with kernel 3.2 using the > instructions here: > http://corysohrakoff.wordpress.com/2011/09/13/enabling-wifi-ap-mode-on-a-gumstix-overo/ > That was also slow. > > Any hints? GSPI or SDIO? What SD host controller? Does the controller support 4-bit mode correctly? What block sizes does it support? Most often the issue is with crappy host controllers that need workarounds or quirks to correctly support the higher speeds that the driver can do. The benchmark I always used was that on a laptop with a Ricoh SD controller, I could easily pull megabits per second even 15 feet away. (that's not to say there aren't inefficiencies in the driver, just that we know that given a good SDHC and a good SDHC driver, that the libertas driver itself is not the bottleneck). Dan -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
