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Date: Thu, 10 Feb 2011 08:41:40 +0100
From: Stanislaw Gruszka <sgruszka@redhat.com>
To: =?utf-8?B?5p2O5pyd5piO?= <chaoming_li@realsil.com.cn>
Cc: "'Larry Finger'" <Larry.Finger@lwfinger.net>,
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Subject: Re: =?utf-8?B?562U5aSN?= =?utf-8?Q?=3A?= about Mac80211 scan issue
Message-ID: <20110210074140.GA2228@redhat.com>
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On Thu, Feb 10, 2011 at 03:03:57PM +0800, 李朝明 wrote:
> > I'm not sure if I understand problem you described. Anyway, 
> > maybe is enaugh to implement ->flush() in rtlwifi to solve 
> > the problem?
> 
> I don't think drv_flush in ieee80211_start_sw_scan is needed, because
> there's no netif_tx_stop_all_queues before it.
> And on my test, all queues still send skb to driver in this drv_flush.

Hmm, there must be something wrong ... there is netif_tx_stop_all_queues
when interface is not MONITOR. Below are corresponding code snippets:

static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
                                                    unsigned long *next_delay)
{
        /* PS will already be in off-channel mode,
         * we do that once at the beginning of scanning.
         */
        ieee80211_offchannel_stop_vifs(local, false);

        /*
         * What if the nullfunc frames didn't arrive?
         */
        drv_flush(local, false);

....

void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local,
                                    bool offchannel_ps_enable)
{
        struct ieee80211_sub_if_data *sdata;

        /*
         * notify the AP about us leaving the channel and stop all
         * STA interfaces.
         */
        mutex_lock(&local->iflist_mtx);
        list_for_each_entry(sdata, &local->interfaces, list) {
                if (!ieee80211_sdata_running(sdata))
                        continue;

                if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
                        set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
...
                if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
                        netif_tx_stop_all_queues(sdata->dev);