[rt2x00-users] [RFC] rt2x00: rt2800: enable STBC

Helmut Schaa helmut.schaa at googlemail.com
Fri May 28 19:10:52 UTC 2010


Am Freitag 28 Mai 2010 schrieb Gertjan van Wingerde:
> On 05/28/10 18:16, Helmut Schaa wrote:
> > Am Freitag 28 Mai 2010 schrieb Gertjan van Wingerde:
> >> On 05/28/10 14:58, Ivo Van Doorn wrote:
> >>> On Fri, May 28, 2010 at 2:31 PM, Helmut Schaa
> >>> <helmut.schaa at googlemail.com> wrote:
> >>>> Am Freitag 28 Mai 2010 schrieb Gertjan van Wingerde:
> >>>>> On 05/28/10 13:35, Helmut Schaa wrote:
> >>>>>> +   if (tx_info->flags & IEEE80211_TX_CTL_STBC)
> >>>>>> +           __set_bit(ENTRY_TXD_HT_STBC, &txdesc->flags);
> >>>>>>
> >>>>>>     /*
> >>>>>>      * Determine HT Mix/Greenfield rate mode
> >>>>>
> >>>>> This doesn't seem to work. In mac80211 the IEEE80211_TX_CTL_STBC is actually a 2-bit field,
> >>>>> so is the field in the TXWI structure of rt2x00. I suggest we keep the stbc field a u16 (or a u8)
> >>>>> and simply copy the value of these two bits into that field.
> >>>>
> >>>> I know what you mean but the ralink drivers only use 0 and 1. Maybe because
> >>>> there are no 3 tx stream devices yet? But you're right, let's keep the stbc
> >>>> field and map everything !=0 to 1 for now?
> >>>
> >>> You might want to check my STBC patch in the experimental branch of rt2x00.git,
> >>> I had coded it yesterday and does use the entire IEEE80211_TX_CTL_STBC field
> >>> of the flag (Note that IEEE80211_TX_CTL_STBC is also 2 bits).
> >>>
> >>
> >> Just checking this patch. It looks indeed like the way to go, if only one buglet is
> >> fixed. I believe the bit-shift is going in the wrong direction. You should use
> >> '>>' instead of '<<' when shifting the STBC value.
> >>
> >> P.S. I guess both you and Helmut are aware that mac80211 does not seem to be setting
> >> this flag currently, so the net-result still will be a no-op.
> > 
> > Yes, I am. The rate control algorithm is setting it. And for example
> > minstrel_ht (which isn't merged yet) will set it ;)
> 
> OK. Good. Where can I find this minstrel_ht?

Felix posted it some time ago (2010-05-13 16:48) on linux-wireless [1]:

[PATCH] mac80211: add the minstrel_ht rate control algorithm

Helmut

[1] http://comments.gmane.org/gmane.linux.kernel.wireless.general/50878



More information about the users mailing list