Andrew Morton wrote:
quoted text
> (cc's added)
>
> On Sun, 08 Aug 2010 11:49:49 +0200
> Andreas<andihartmann@01019freenet.de>  wrote:
>
>> Hello!
>>
>> I've got the following hardware
>>
>>
>> 01:05.0 Network controller: RaLink RT2561/RT61 rev B 802.11g
>>           Subsystem: Micro-Star International Co., Ltd. Device b833
>>           Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop-
>> ParErr- Stepping- SERR- FastB2B- DisINTx-
>>           Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=slow>TAbort-
>> <TAbort-<MAbort->SERR-<PERR- INTx-
>>           Latency: 128, Cache Line Size: 64 bytes
>>           Interrupt: pin A routed to IRQ 21
>>           Region 0: Memory at cc000000 (32-bit, non-prefetchable) [size=32K]
>>           Capabilities: [40] Power Management version 2
>>                   Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA
>> PME(D0-,D1-,D2-,D3hot-,D3cold-)
>>                   Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
>>           Kernel driver in use: ndiswrapper
>>
>>
>> running on a 32bit notebook with kernel 2.6.34-12-desktop (OpenSuSE
>> 11.3). There is no difference between the compat-wireless-modules
>> 2010-07-20 and the original modules shipped with the openSuSE 11.3 kernel.
>>
>> If the rt61-chip is connected to a AP using rt61pci, the best
>> throughput, which can be achieved (at the same place), is about 1,7
>> MBytes/s.
>>
>> kernel: [  656.112190] cfg80211: Calling CRDA to update world regulatory
>> domain
>> kernel: [  656.112267] cfg80211: Calling CRDA for country: DE
>> kernel: [  656.169518] cfg80211: Regulatory domain changed to country: DE
>> kernel: [  656.169524]     (start_freq - end_freq @ bandwidth),
>> (max_antenna_gain, max_eirp)
>> kernel: [  656.169528]     (2400000 KHz - 2483500 KHz @ 40000 KHz),
>> (N/A, 2000 mBm)
>> kernel: [  656.169532]     (5150000 KHz - 5350000 KHz @ 40000 KHz),
>> (N/A, 2000 mBm)
>> kernel: [  656.169535]     (5470000 KHz - 5725000 KHz @ 40000 KHz),
>> (N/A, 2698 mBm)
>> kernel: [  656.206228] rt61pci 0000:01:05.0: PCI INT A ->  GSI 21 (level,
>> low) ->  IRQ 21
>> kernel: [  656.219941] phy0: Selected rate control algorithm 'minstrel'
>> kernel: [  656.222216] Registered led device: rt61pci-phy0::radio
>> kernel: [  656.222658] Registered led device: rt61pci-phy0::assoc
>> kernel: notebook1 ifup:     wlan0     device: RaLink RT2561/RT61 rev B
>> 802.11g
>>
>>
>>
>> wlan0     IEEE 802.11bg  ESSID:"--------"
>>             Mode:Managed  Frequency:2.412 GHz  Access Point: some AP
>>             Bit Rate=1 Mb/s   Tx-Power=5 dBm
>>             Retry  long limit:7   RTS thr:off   Fragment thr:off
>>             Encryption key:off
>>             Power Management:off
>>             Link Quality=38/70  Signal level=-72 dBm
>>             Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>>             Tx excessive retries:0  Invalid misc:0   Missed beacon:0
>>
>> The throughput is measured with ping -f -s 7000 and xosview -n.
>>
>>
>>
>>
>> If I'm using ndiswrapper with the windows driver, first of all, I can
>> see additional information in iwconfig:
>>
>> wlan0     IEEE 802.11g  ESSID:"--------"
>>             Mode:Managed  Frequency:2.412 GHz  Access Point: some AP
>>             Bit Rate=54 Mb/s   Tx-Power:20 dBm   Sensitivity=-121 dBm
>>             RTS thr=2347 B   Fragment thr=2346 B
>>             Encryption key:some key   Security mode:restricted
>>             Power Management:off
>>             Link Quality:62/100  Signal level:-56 dBm  Noise level:-96 dBm
>>             Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>>             Tx excessive retries:0  Invalid misc:0   Missed beacon:0
>>
>>
>> There is a switch for sensitivity (which is not supported with rt61pci)
>> and the link quality compared with ndiswrapper is worse (38% to 62%).
>>
>> The following is remarkably too:
>> ndiswrapper uses a Tx-Power of 20 dBm, rt61pci only 5 dBm. I don't know,
>> why rt61pci uses 5 dBm. It's a hard limit and I can't set it on a value
>> higher than 5 unless the driver is patched. Nevertheless, setting a
>> higher value (of 20 dBm) by patch does not mean to get a better performance.

That's wrong. I detected, that there is a great difference, because if 
you start the unpatched driver directly after the boot, the link isn't 
useable at all.
I can't see any difference if the patched driver is loaded once and 
removed and the unpatched is loaded afterwards without rebooting between.

The patch is:

--- rt61pci.c.orig      2010-07-20 21:03:02.000000000 +0200
+++ rt61pci.c   2010-08-14 10:27:52.708008193 +0200
@@ -2661,13 +2661,17 @@
         spec->channels_info = info;

         tx_power = rt2x00_eeprom_addr(rt2x00dev, EEPROM_TXPOWER_G_START);
-       for (i = 0; i < 14; i++)
-               info[i].tx_power1 = TXPOWER_FROM_DEV(tx_power[i]);
+       for (i = 0; i < 14; i++) {
+               // info[i].tx_power1 = TXPOWER_FROM_DEV(tx_power[i]);
+               info[i].tx_power1 = 25;
+               }

         if (spec->num_channels > 14) {
                 tx_power = rt2x00_eeprom_addr(rt2x00dev, 
EEPROM_TXPOWER_A_START);
-               for (i = 14; i < spec->num_channels; i++)
-                       info[i].tx_power1 = TXPOWER_FROM_DEV(tx_power[i]);
+               for (i = 14; i < spec->num_channels; i++) {
+                       // info[i].tx_power1 = 
TXPOWER_FROM_DEV(tx_power[i]);
+                       info[i].tx_power1 = 25;
+                       }
         }

         return 0;



Kind regards,
Andreas
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