On 09/02/2012 01:50 PM, coekbe wrote:
Hi All,
Beaconing support in rtl8192cu (AP and ad-hoc modes) was already
mostly there, but code for actually sending out beacon frames was
missing. The following patch works for me, meaning that I can use
hostapd to set up a functioning AP.
Beaconing in rtl8192cu seems to work such that the user needs to
explicitly send one beacon frame, which the hardware then starts
repeating. The explicitly sent frames show up in hostapd's mon.wlan0
and then hostapd also prints out a message "unknown mgmt cb frame
subtype 8". I don't know how to fix that. It doesn't seem to matter,
though.
Also, hostapd.conf should have "dtim_period=1", since the hardware
doesn't change dtim count in the beacon frames it sends. Furthermore,
the period is hardcoded to 1 in the realtek vendor driver. Is there a
way for a driver to inform mac80211 and hostapd about this limitation?
How does the patch look? My knowledge in this area is very limited:
basically, I guess the patch is ok, since my kernel doesn't panic. :)
(I realize that the patch modifies the common rtlwifi code, so it
should condition the new beaconing code for rtl8192cu only.)
Changing rtlwifi is not acceptable when you only wish to modify a single driver.
That code in any other routine than usb.c will affect all the other drivers.
I used my hostapd script to start an AP with rtl8192cu using the ESSID "TEST".
After I did tat, I did an 'iw scan' with a different interface and got
BSS 00:1f:1f:c8:8e:cb (on wlan2)
TSF: 3249538351 usec (0d, 00:54:09)
freq: 2462
beacon interval: 100
capability: ESS Privacy ShortSlotTime (0x0411)
signal: -30.00 dBm
last seen: 24 ms ago
SSID: TEST
Supported rates: 1.0* 2.0* 5.5* 11.0* 6.0 9.0 12.0 18.0
DS Parameter set: channel 11
Country: US Environment: Indoor/Outdoor
Channels [1 - 11] @ 20 dBm
ERP: Barker_Preamble_Mode
Extended supported rates: 24.0 36.0 48.0 54.0
RSN: * Version: 1
* Group cipher: CCMP
* Pairwise ciphers: CCMP
* Authentication suites: PSK
* Capabilities: 16-PTKSA-RC (0x000c)
HT capabilities:
Capabilities: 0x186c
HT20
SM Power Save disabled
RX HT20 SGI
RX HT40 SGI
No RX STBC
Max AMSDU length: 7935 bytes
DSSS/CCK HT40
Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
Minimum RX AMPDU time spacing: 16 usec (0x07)
HT TX/RX MCS rate indexes supported: 0-7, 32
HT operation:
* primary channel: 11
* secondary channel offset: no secondary
* STA channel width: 20 MHz
* RIFS: 0
* HT protection: no
* non-GF present: 0
* OBSS non-GF present: 0
* dual beacon: 0
* dual CTS protection: 0
* STBC beacon: 0
* L-SIG TXOP Prot: 0
* PCO active: 0
* PCO phase: 0
WMM: * Parameter version 1
* BE: CW 15-1023, AIFSN 3
* BK: CW 15-1023, AIFSN 7
* VI: CW 7-15, AIFSN 2, TXOP 3008 usec
* VO: CW 3-7, AIFSN 2, TXOP 1504 usec
Obviously, the rtl8192cu is beaconing with no changes to the wireless-testing
code. This driver has the hooks to set the beacon time, but it is not being
changed - that needs investigation. A second machine could authenticate and
associate; however, I could get no ping throughput.
I will be looking at this driver when I get time; however, I must warn that I
consider problems using these drivers as an AP to have low priority. You can;
however, use your patch to make it work, but that patch will not be accepted.
Larry
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