On Tuesday 09 October 2007, Johannes Berg wrote: > On Tue, 2007-10-09 at 19:32 +0200, Ivo van Doorn wrote: > > > Well that is my point, if the documentation is correct then rt2500usb > > has 2 locations to initialize the IFS. So it would always be set and the question > > would be what the impact would be to set the IFS per packet only. > > But that is something I need to test with just some experiments. > > Well, it's not too strange that it has two places since there's the SIFS > too which is needed for ACK/CTS timing, these packets aren't sent from > the host so you can't have those timings in a per-packet descriptor. You mean things like ACK_TIMEOUT, those are all seperate registers in the Ralink hardware. ButI think I should be more clearer on this, rt2500pci and rt2500usb are basically the same chipset but only the bus type is different. What is notable is that _only_ rt2500usb has this IFS register, none of the other Ralink chipsets (including rt2500pci) have it. > > This means that the device would be able to operate correctly for > > 802.11B even with the 802.11G timing initialization. Because according > > to the way the legacy driver is setup, working in 802.11G while working > > with the CCK rates would be possible. > > This also means associating to 802.11B AP's while in 802.11G mode. > > So we might be making a big deal out of something while the source > > of the problem is very simple: The legacy driver code is just wrong. ;) > > Well, no, if you have a pure 802.11B AP then you have to use the 11B > slot timing, if you have a G AP then it'll tell you which timing to use > (I think) True, but in G mode you are compatible with B. The legacy driver doesn't switch back to B mode when the AP is in B mode. This means that it will be using the G timing values. Even if the G AP is telling which timing it is using, it is ignored by the legacy driver since the timing value is hardcoded for both B as G mode. Ivo - 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
