Hi Arend,
On Tue, 2023-04-25 at 12:01 +0200, Arend van Spriel wrote:
> My brain is tripping over a field in struct ieee80211_iface_combination,
> ie. the num_different_channels. Looking at the name I tend to think that
> num_different_channel = 0 means the interfaces must all operate on the
> same channel. However, in most places it is configured as 1 or more. The
> documentation in cfg80211.h [1] is not unambiguous about it in my
> opinion. By now it probably depends on how user-space uses it.
Well it's not valid for it to be 0 in the first place:
static int wiphy_verify_combinations(struct wiphy *wiphy)
{
...
for (i = 0; i < wiphy->n_iface_combinations; i++) {
...
for (i = 0; i < wiphy->n_iface_combinations; i++) {
...
/* Need at least one channel */
if (WARN_ON(!c->num_different_channels))
return -EINVAL;
So really what was meant that _1_ means you only have a single channel,
and so on. Are you tripping over the "different"? The way I read it, is
that with all the interfaces you have, you can have N different
channels, i.e. looking at it "globally". It seems maybe you're more
interpreting it as "additionally" to the first interface?
johannes
