Enable tx mimo for iwn driver (Centrino N wireless cards) #424
Conversation
|
Thank you for the contribution, I am busy for these days, will take sometime to have a look. |
|
No worries, take your time. |
The tx structure is reused, and all fields need properly initialize. Without set proper rflags value, certain packet like mgmt frame may be sent at wrong coding scheme. This is discovered during a failed addba negotiation.
|
please centrino 6235 |
|
@ihsanbudiman I don't have a copy of 6235, and it should work in some degree. |
| break; | ||
| } | ||
| if (ic->ic_flags & IEEE80211_F_USEPROT) | ||
| if (sc->hw_type != IWN_HW_REV_TYPE_4965) |
There was a problem hiding this comment.
@pigworlds Hi :), do you remember where does the code from? It seems that it is different from Linux
There was a problem hiding this comment.
I looked at the history and can only find they were introduced in pigworlds@38bbc0c and pigworlds@bffc12b.
I don't recall the reason for this flag, it could be a trial and error and this works. This might be a bug too.
| tab = ht_plcp; | ||
| rflags |= IWN_RFLAG_MCS; | ||
| if (sgi_ok) | ||
| rflags |= IWN_RFLAG_SGI; |
There was a problem hiding this comment.
@pigworlds A weird thing is that the Tx performance drops seriously when SGI is enabled on 5GHz/40MHz channels, do you have the same experience? My card is N-6235.
There was a problem hiding this comment.
I didn't have the same experience with my Intel N-6205 connecting to Netgear R7800 router. It shows both Tx/Rx at 300.0 Mbit/s, 40 MHz, MCS 15, Short GI, while running iperf3 test.
I recall that with certain routers, the performance drops quickly when I move the laptop around, and stable when the laptop remains stationary. I don't remember specific SGI settings of those routers.
This change enables the tx mimo for iwn driver on old wireless cards.
The iwn_rates table was pervious only include mcs rate up to 7. The link quality table generation didn't handle mimo rates.
This change port over the iwn_rates and link quality tables from iwm driver, plus additional logging.
A test on Centrino N 6205 shows slight increase of tx rate around 30mbps using iperf3.