Hi all, first of all thank you all for your help. I now have some news to report. Using your hint about timing I've inserted a bunch of udelays around the read/write functions that get called from _rtl92c_write_fw and got rid of the "detected XactErr len 0/0 retry" errors. Then I just tried to use the WLAN adapter and it worked. Afterwards, I've removed udelays and tried it again and guess what... everything still worked. I do not really know if I should consider these errors harmless but it looks as if they are. What do you think? I do however have something fishy to report, but this is probably an off-topic for linux-usb mailing list so I'll just mention it here briefly for completeness. Fist, I've compared the speed of the rtl8192cu vs 8192cu in 3.4 kernel. The latter one is the Realtek's driver. I've did many download tests of the same file and it turns out 8192cu is 1.5 times faster. Things haven't improved since then. The 3.12-rc1 rtl8192cu shows the same performance as in 3.4. In addition with 3.12-rc1 I get some strange messages in the dmesg [1]. Best regards, Arokux [1] http://sprunge.us/dide -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html