Re: [PATCH 02/31] staging: wfx: do not send CAB while scanning

Jérôme Pouiller
2021-09-10T16:54:47Z

On Friday 10 September 2021 18:31:00 CEST Kari Argillander wrote:
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>
> On Fri, Sep 10, 2021 at 06:04:35PM +0200, Jerome Pouiller wrote:
> > From: Jérôme Pouiller <jerome.pouiller@silabs.com>
> >
> > During the scan requests, the Tx traffic is suspended. This lock is
> > shared by all the network interfaces. So, a scan request on one
> > interface will block the traffic on a second interface. This causes
> > trouble when the queued traffic contains CAB (Content After DTIM Beacon)
> > since this traffic cannot be delayed.
> >
> > It could be possible to make the lock local to each interface. But It
> > would only push the problem further. The device won't be able to send
> > the CAB before the end of the scan.
> >
> > So, this patch just ignore the DTIM indication when a scan is in
> > progress. The firmware will send another indication on the next DTIM and
> > this time the system will be able to send the traffic just behind the
> > beacon.
> >
> > The only drawback of this solution is that the stations connected to
> > the AP will wait for traffic after the DTIM for nothing. But since the
> > case is really rare it is not a big deal.
> >
> > Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
> > ---
> > drivers/staging/wfx/sta.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c
> > index a236e5bb6914..d901588237a4 100644
> > --- a/drivers/staging/wfx/sta.c
> > +++ b/drivers/staging/wfx/sta.c
> > @@ -629,8 +629,18 @@ int wfx_set_tim(struct ieee80211_hw *hw, struct ieee80211_sta *sta, bool set)
> >
> > void wfx_suspend_resume_mc(struct wfx_vif *wvif, enum sta_notify_cmd notify_cmd)
> > {
> > + struct wfx_vif *wvif_it;
> > +
> > if (notify_cmd != STA_NOTIFY_AWAKE)
> > return;
> > +
> > + // Device won't be able to honor CAB if a scan is in progress on any
> > + // interface. Prefer to skip this DTIM and wait for the next one.
>
> In one patch you drop // comments but you introduce some of your self.

Indeed. When I wrote this patch, I didn't yet care to this issue. Is it
a big deal since it is fixed in patch 27?

--
Jérôme Pouiller