On 11/17/2011 03:28 AM, Johannes Berg wrote:
Ben, sorry for the delay, I was too busy thinking about other stuff.
On Thu, 2011-11-10 at 11:25 -0800, Ben Greear wrote:
But, I don't think it is going to work..or at least if it can, I
don't see a good way to do it.
I'm stuck in the ieee80211_ht_cap_ie_to_sta_ht_cap method. With
my original patch, I apply overrides here, at the bottom of the
method. If we're associated (or started associating)
and user asked for over-rides, we'll apply requested overrides, else
nothing will change because the over-rides mask is not set.
But, if I have to use pre-computed values here then I need to
be certain they are set properly. If association has been
requested, then that is fine. But, what about the
sta_apply_parameters() method? Can we guarantee that association has
been requested when this method is called? I think we cannot,
and if not, then I cannot use pre-computed sdata->used_ht_caps.
I could attempt to set a flag when used_ht_caps
has been calculated, and add a check for that, but that is yet another piece
of computed state that could be stale if we make a mistake somewhere.
We can't, but can't we like assign sdata->ht_caps = sband->ht_caps? Or
maybe even calculate restricted HT caps for both 2.4 and 5 GHz?
Basically what I was thinking is this:
struct sub_if_data {
...
struct ieee80211_sta_ht_cap ht_cap[num_bands];
...
};
So we'd have to copy this data from sbands[] upon creation
of the interface to make sure it is always initialized?
This would allow us to easily support the overrides for
non-station interfaces, so I do like that benefit.
Can the sbands[] data ever change for any reason once
an interface is created? If not, then probably this is
doable. If it can change, then we are screwed.
We'd use *that* everywhere, and when associating we calculate
sdata->ht_cap[band] = apply_overrides(sbands[band]->ht_cap);
and when disassociating we simply
memcpy(sdata->ht_cap[band], sbands[band]->ht_cap, ...);
or so? Then we can always use sdata->ht_cap[bands] instead of
sband->ht_caps everywhere, and overrides are implicit.
Was this what you attempted?
I was trying to use a single calculated-ht-cap struct instead
of one for each band, and I was trying to put it into sdata->u.sta,
which made initialization issues much more scary for me.
It seems you are basically wanting to copy the sband[] data
local to each interface (sdata), and then we would remove sband from most
(or all?) of the method calls that deal with sband->ht_caps?
Looks like quite a bit of code churn, and probably requiring at least two
patches:
* Get rid of sband usage by copying the sband data into sdata
* Add the over-ride logic
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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