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1 | Host AP driver - Frequently Asked Questions |
2 | =========================================== | |
3 | ||
4 | 1. What does "GetNextTuple: No more items" mean in hostap_cs initialization? | |
5 | 2. Why RX does not work? | |
6 | What does "NETDEV WATCHDOG: wlan0: transmit timed out" mean? | |
7 | (interrupt delivery problems) | |
8 | 3. What is wrong with Host AP mode in secondary (station) firmware v1.4.2? | |
9 | 4. What is causing 'Unresolved symbols' in depmod/modprobe? | |
10 | 5. How can I upgrade Prism2/2.5/3 firmware? | |
11 | 6. Why did I get two network interfaces (wlan0 and wifi0) even when I have | |
12 | only one wireless card? | |
13 | 7. Why does my D-Link DWL-650 rev. P1 or D-Link DWL-520 rev. E1 (or any other | |
14 | card with small flash) card fail? | |
15 | 8. Does Host AP driver support IEEE 802.11a and 802.11g? Does it support | |
16 | chipsets other than Prism 2/2.5/3? | |
17 | ||
18 | ||
19 | ||
20 | 1. What does "GetNextTuple: No more items" mean in hostap_cs initialization? | |
21 | ||
22 | This is one of the most often reported problems in getting the | |
23 | hostap_cs.o driver working. It is usually reported for D-Link DWL-650 | |
24 | PC Card, e.g., on ISA-to-PCMCIA adapter. Later versions of the driver | |
25 | report this also with "Vcc mismatch - skipping this entry". | |
26 | ||
27 | Most common reason for getting this is a mismatch in voltage | |
28 | configuration. The driver tries to make sure that the voltage (Vcc) | |
29 | configuration in CIS and the slot match each other. It refuses to | |
30 | initialize the card if the card CIS does not include a CFTABLE entry | |
31 | with a matching Vcc value. This seems to be a problem for some cases | |
32 | since the CIS is invalid or the reported voltage is incorrect. | |
33 | ||
34 | As a workaround, the driver supports a module parameter ignore_cis_vcc | |
35 | that can be used to skip this verification. This can be enabled by | |
36 | setting ignore_cis_vcc=1 in /etc/pcmcia/hostap_cs.conf (commented | |
37 | example line in the end of file). This can also be tested by manually | |
38 | loading the module with 'modprobe hostap_cs ignore_cis_vcc=1' before | |
39 | inserting the card). | |
40 | ||
41 | ||
42 | ||
43 | 2. Why RX does not work? | |
44 | What does "NETDEV WATCHDOG: wlan0: transmit timed out" mean? | |
45 | (interrupt delivery problems) | |
46 | ||
47 | If the driver does not seem to receive any packets or sending packets | |
48 | results in "NETDEV WATCHDOG: wlan0: transmit timed out", the reason is | |
49 | probably in interrupt delivery problems. This is quite common with | |
50 | PCI-to-PCMCIA adapters. Newer than 2002-05-19 of the driver have a | |
51 | test that will report this after the initialization ("wlan: Possible | |
52 | interrupt delivery problem"). Another method for checking this is to | |
53 | observer whether interrupt counters in /proc/interrupts increase for | |
54 | hostap_cs/wlan0 entry. | |
55 | ||
56 | Adding suitable irq_mode=# setting in PCIC_OPTS line of | |
57 | pcmcia-configuration is the most common fix for this. pcmcia-cs HOWTO | |
58 | has more information on how to debug and fix interrupt delivery | |
59 | problems at | |
60 | http://pcmcia-cs.sourceforge.net/ftp/doc/PCMCIA-HOWTO-5.html#irqmode | |
61 | ||
62 | ||
63 | ||
64 | 3. What is wrong with Host AP mode in secondary (station) firmware v1.4.2? | |
65 | ||
66 | It looks like secondary firmware v1.4.2 sends beacon frames properly, | |
67 | but does not respond to probe requests. With most station cards, this | |
68 | prevents authentication and association and thus, in practice, no data | |
69 | frames can be sent. It has been reported that at least some Cisco | |
70 | Aironet 350 cards can associate with Host AP mode even with firmware | |
71 | v1.4.2 (i.e., without receiving probe response), but Prism2 and | |
72 | Lucent/ORiNOCO/Agere seem to require probe response and they do not | |
73 | thus associate with AP using v1.4.2 firmware. | |
74 | ||
75 | This is fixed in later secondary firmware versions; probably already | |
76 | in 1.4.3, but at least 1.4.9 has been tested to work. In other words, | |
77 | this problem can be fixed by upgrading card firmware. | |
78 | ||
79 | ||
80 | ||
81 | 4. What is causing 'Unresolved symbols' in depmod/modprobe? | |
82 | ||
83 | Installation of Host AP driver (e.g, 'make install_pccard') may report | |
84 | unresolved symbols when running depmod. These are usually caused with | |
85 | mismatch in kernel configuration for modversions. | |
86 | ||
87 | Example: | |
88 | ||
89 | depmod reports unresolved symbol 'eth_type_trans' (this is without | |
90 | modversions): | |
91 | depmod: eth_type_trans | |
92 | ||
93 | but kernel was really configured with CONFIG_MODVERSIONS: | |
94 | ||
95 | # grep eth_type_trans /proc/ksyms | |
96 | c01b66c0 eth_type_trans_Rdb9cd26f | |
97 | ||
98 | (notice the _R... postfix) | |
99 | ||
100 | This happens if the kernel configuration given to Host AP driver's | |
101 | Makefile (.config in KERNEL_PATH) has not CONFIG_MODVERSIONS, but the | |
102 | running kernel is compiled with it. | |
103 | If the kernel were configured without modversions, /proc/ksyms would | |
104 | show the symbols with _R... postfix: | |
105 | ||
106 | ||
107 | Mismatches in kernel configuration can be fixed by using the same | |
108 | configuration (i.e., Linux kernel .config) for both the kernel and the | |
109 | driver. If you are using a kernel from a distribution installation | |
110 | (i.e., you have not compiled it yourself), you will need to create a | |
111 | matching .config file somehow. This depends on the distribution you | |
112 | are using, but 'make oldconfig' in kernel source directory might work | |
113 | with some distributions. If you compile the kernel yourself, it will | |
114 | be easier, since you already have to have created the correct .config | |
115 | file. | |
116 | ||
117 | ||
118 | ||
119 | 5. How can I upgrade Prism2/2.5/3 firmware? | |
120 | ||
121 | Prism2/2.5/3 cards and Host AP driver support two different mechanism | |
122 | of upgrading the card firmware. Firmware images (primary and station) | |
123 | can be downloaded either into volatile memory (RAM download) or | |
124 | non-volatile memory (flash upgrade). Firmware images downloaded into | |
125 | volatile memory are lost when the card is resetted, so they are quite | |
126 | safe. Flash upgrade with incorrect images may cause permanent problems | |
127 | (i.e., render the card useless), so certain amount of caution is | |
128 | always recommended for this. | |
129 | ||
130 | Note! Some of the older versions of Host AP driver or prism2_srec had | |
131 | fatal bugs in flash upgrade. Only versions 0.1.0 or newer should be | |
132 | used when performing non-volatile flash upgrade! | |
133 | ||
134 | utils/prism2_srec (run 'make' in utils directory to build this) is a | |
135 | tool that can be instructed Host AP driver to download firmware image | |
136 | into the wlan card. Brief usage information is available by running | |
137 | this program without any command line parameters. Please note, that | |
138 | the downloading support is disabled in the default Host AP driver | |
139 | build. You will need to change this by defining | |
140 | PRISM2_DOWNLOAD_SUPPORT (and PRISM2_NON_VOLATILE_DOWNLOAD if you want | |
141 | to update flash); see driver/modules/hostap_config.h for more details. | |
142 | ||
143 | Jun Sun has written a mini-howto on flashing Intersil Prism | |
144 | Chipsets. This is available at http://linux.junsun.net/intersil-prism/. | |
145 | ||
146 | ||
147 | ||
148 | 6. Why did I get two network interfaces (wlan0 and wifi0) even when I have | |
149 | only one wireless card? | |
150 | ||
151 | Host AP driver supports multiple virtual interfaces per wireless | |
152 | card. wifi0 is the master radio interface and wlan0 is the first | |
153 | virtual interface for this radio. Other virtual interfaces are wlan0ap | |
154 | (for hostapd), and one interface per WDS link. | |
155 | ||
156 | In most cases, one should ignore wifi0 interface and just use wlan0 | |
157 | interface. In other words, assign IP address to wlan0, not wifi0 and | |
158 | in general, just ignore the wifi0 interface. | |
159 | ||
160 | ||
161 | ||
162 | 7. Why does my D-Link DWL-650 rev. P1 or D-Link DWL-520 rev. E1 (or any other | |
163 | card with small flash) card fail? | |
164 | ||
165 | Some of the new Prism3-based cards use a smaller flash chip that does | |
166 | not include full firmware for the card. For example, D-Link DWL-650 | |
167 | rev. P1 and D-Link DWL-520 rev. E1 are such cards. These cards require | |
168 | that the firmware is downloaded to the card during initialization. See | |
169 | utils/hostap_fw_load for example commands on doing this. | |
170 | ||
171 | ||
172 | ||
173 | 8. Does Host AP driver support IEEE 802.11a and 802.11g? Does it support | |
174 | chipsets other than Prism 2/2.5/3? | |
175 | ||
176 | Host AP driver supports only Intersil Prism chipsets, versions 2, 2.5, | |
177 | and 3. Those chipsets support IEEE 802.11b only; other chipsets are | |
178 | not supported. All utilities distributed with Host AP driver except | |
179 | wpa_supplicant work only with Host AP driver, so they are limited to | |
180 | the same hardware. wpa_supplicant works with other drivers, including | |
181 | those that support 802.11a and 802.11g. |