Question on beacon-miss offloading.

Question on beacon-miss offloading.

[Ben Greear]

In my ath10k CT firmware, I am disabling the beacon-miss offloading
to save space and because it will not work with lots of virtual
stations.

But, it must be that I need some way to tell the stack that this
feature is not enabled, because when suddenly kill my AP, then
the ath10k station connected to it shows endless 'beacon loss' events
in 'iw events' output, but it never actually loses connection.

Stock firmware works fine, so probably I just need to disable
some feature flag when registering the ath10k hardware
when using CT firmware.

With stock firmware, I see a quick dissassociation due to inactivity.

I am having poor luck finding how a driver tells the stack
it has beacon miss offload or not, so, does anyone know how
this is controlled?

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Question on beacon-miss offloading.

[Ben Greear]

On 06/11/2015 02:07 PM, Ben Greear wrote:
> In my ath10k CT firmware, I am disabling the beacon-miss offloading
> to save space and because it will not work with lots of virtual
> stations.
> 
> But, it must be that I need some way to tell the stack that this
> feature is not enabled, because when suddenly kill my AP, then
> the ath10k station connected to it shows endless 'beacon loss' events
> in 'iw events' output, but it never actually loses connection.
> 
> Stock firmware works fine, so probably I just need to disable
> some feature flag when registering the ath10k hardware
> when using CT firmware.
> 
> With stock firmware, I see a quick dissassociation due to inactivity.
> 
> I am having poor luck finding how a driver tells the stack
> it has beacon miss offload or not, so, does anyone know how
> this is controlled?

I still am not sure why stock firmware works, but it appears
the reason mine is failing is that the ACK status for mgt frames
is always set to TRUE since the ath10k wmi-mgt-tx API is so
lame.  So, mac80211 does a probe, ath10k lies and says it was
acked, and mac80211 then things all is well for another few
seconds.

So, I think I'll try to come up with some way to report
proper tx-status for wmi-mgt-frames in my firmware....

Thanks,
Ben


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Question on beacon-miss offloading.

[Michal Kazior]

On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
> On 06/11/2015 02:07 PM, Ben Greear wrote:
>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>> to save space and because it will not work with lots of virtual
>> stations.
>>
>> But, it must be that I need some way to tell the stack that this
>> feature is not enabled, because when suddenly kill my AP, then
>> the ath10k station connected to it shows endless 'beacon loss' events
>> in 'iw events' output, but it never actually loses connection.
>>
>> Stock firmware works fine, so probably I just need to disable
>> some feature flag when registering the ath10k hardware
>> when using CT firmware.
>>
>> With stock firmware, I see a quick dissassociation due to inactivity.
>>
>> I am having poor luck finding how a driver tells the stack
>> it has beacon miss offload or not, so, does anyone know how
>> this is controlled?
>
> I still am not sure why stock firmware works, but it appears
> the reason mine is failing is that the ACK status for mgt frames
> is always set to TRUE since the ath10k wmi-mgt-tx API is so
> lame.  So, mac80211 does a probe, ath10k lies and says it was
> acked, and mac80211 then things all is well for another few
> seconds.

mac80211 shouldn't do a Probe Req to an AP on beacon loss because
ath10k advertises it supports tx-status report. Hence mac80211 should
use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
tx-frm.

But then again: NullFunc status reporting via htt tx-frm was broken on
10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.

This problem has been effectively obscured on stock 10.1 by the
offloaded beacon miss.


Michał

Re: Question on beacon-miss offloading.

[Ben Greear]

On 06/11/2015 11:03 PM, Michal Kazior wrote:
> On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
>> On 06/11/2015 02:07 PM, Ben Greear wrote:
>>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>>> to save space and because it will not work with lots of virtual
>>> stations.
>>>
>>> But, it must be that I need some way to tell the stack that this
>>> feature is not enabled, because when suddenly kill my AP, then
>>> the ath10k station connected to it shows endless 'beacon loss' events
>>> in 'iw events' output, but it never actually loses connection.
>>>
>>> Stock firmware works fine, so probably I just need to disable
>>> some feature flag when registering the ath10k hardware
>>> when using CT firmware.
>>>
>>> With stock firmware, I see a quick dissassociation due to inactivity.
>>>
>>> I am having poor luck finding how a driver tells the stack
>>> it has beacon miss offload or not, so, does anyone know how
>>> this is controlled?
>>
>> I still am not sure why stock firmware works, but it appears
>> the reason mine is failing is that the ACK status for mgt frames
>> is always set to TRUE since the ath10k wmi-mgt-tx API is so
>> lame.  So, mac80211 does a probe, ath10k lies and says it was
>> acked, and mac80211 then things all is well for another few
>> seconds.
>
> mac80211 shouldn't do a Probe Req to an AP on beacon loss because
> ath10k advertises it supports tx-status report. Hence mac80211 should
> use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
> tx-frm.
>
> But then again: NullFunc status reporting via htt tx-frm was broken on
> 10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.
>
> This problem has been effectively obscured on stock 10.1 by the
> offloaded beacon miss.

For what it's worth, I looked at the 4.0.4 ath10k yesterday, and it appears it
ignores the message that the 10.1 firmware sends when beacon loss happens
anyway.  Maybe I misread the firmware code..it's a pile of indirection.

Do you know how the firmware is supposed to signal beacon loss to
the host (from the host's perspective).

Thanks,
Ben


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Question on beacon-miss offloading.

[Krishna Chaitanya]

On Fri, Jun 12, 2015 at 6:59 PM, Ben Greear <greearb@candelatech.com> wrote:
>
>
> On 06/11/2015 11:03 PM, Michal Kazior wrote:
>>
>> On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
>>>
>>> On 06/11/2015 02:07 PM, Ben Greear wrote:
>>>>
>>>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>>>> to save space and because it will not work with lots of virtual
>>>> stations.
>>>>
>>>> But, it must be that I need some way to tell the stack that this
>>>> feature is not enabled, because when suddenly kill my AP, then
>>>> the ath10k station connected to it shows endless 'beacon loss' events
>>>> in 'iw events' output, but it never actually loses connection.
>>>>
>>>> Stock firmware works fine, so probably I just need to disable
>>>> some feature flag when registering the ath10k hardware
>>>> when using CT firmware.
>>>>
>>>> With stock firmware, I see a quick dissassociation due to inactivity.
>>>>
>>>> I am having poor luck finding how a driver tells the stack
>>>> it has beacon miss offload or not, so, does anyone know how
>>>> this is controlled?
>>>
>>>
>>> I still am not sure why stock firmware works, but it appears
>>> the reason mine is failing is that the ACK status for mgt frames
>>> is always set to TRUE since the ath10k wmi-mgt-tx API is so
>>> lame.  So, mac80211 does a probe, ath10k lies and says it was
>>> acked, and mac80211 then things all is well for another few
>>> seconds.
>>
>>
>> mac80211 shouldn't do a Probe Req to an AP on beacon loss because
>> ath10k advertises it supports tx-status report. Hence mac80211 should
>> use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
>> tx-frm.
>>
>> But then again: NullFunc status reporting via htt tx-frm was broken on
>> 10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.
>>
>> This problem has been effectively obscured on stock 10.1 by the
>> offloaded beacon miss.
>
>
> For what it's worth, I looked at the 4.0.4 ath10k yesterday, and it appears
> it
> ignores the message that the 10.1 firmware sends when beacon loss happens
> anyway.  Maybe I misread the firmware code..it's a pile of indirection.
>
> Do you know how the firmware is supposed to signal beacon loss to
> the host (from the host's perspective).

Normally driver would advertise IEEE80211_HW_CONNECTION_MONITOR
to disable mac80211 from tracking connection. and driver should call
ieee80211_beacon_loss up on receiving beacon loss event from FW
which triggers disconnection in mac80211.

Re: Question on beacon-miss offloading.

[Ben Greear]

On 06/12/2015 07:10 AM, Krishna Chaitanya wrote:
> On Fri, Jun 12, 2015 at 6:59 PM, Ben Greear <greearb@candelatech.com> wrote:
>>
>>
>> On 06/11/2015 11:03 PM, Michal Kazior wrote:
>>>
>>> On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
>>>>
>>>> On 06/11/2015 02:07 PM, Ben Greear wrote:
>>>>>
>>>>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>>>>> to save space and because it will not work with lots of virtual
>>>>> stations.
>>>>>
>>>>> But, it must be that I need some way to tell the stack that this
>>>>> feature is not enabled, because when suddenly kill my AP, then
>>>>> the ath10k station connected to it shows endless 'beacon loss' events
>>>>> in 'iw events' output, but it never actually loses connection.
>>>>>
>>>>> Stock firmware works fine, so probably I just need to disable
>>>>> some feature flag when registering the ath10k hardware
>>>>> when using CT firmware.
>>>>>
>>>>> With stock firmware, I see a quick dissassociation due to inactivity.
>>>>>
>>>>> I am having poor luck finding how a driver tells the stack
>>>>> it has beacon miss offload or not, so, does anyone know how
>>>>> this is controlled?
>>>>
>>>>
>>>> I still am not sure why stock firmware works, but it appears
>>>> the reason mine is failing is that the ACK status for mgt frames
>>>> is always set to TRUE since the ath10k wmi-mgt-tx API is so
>>>> lame.  So, mac80211 does a probe, ath10k lies and says it was
>>>> acked, and mac80211 then things all is well for another few
>>>> seconds.
>>>
>>>
>>> mac80211 shouldn't do a Probe Req to an AP on beacon loss because
>>> ath10k advertises it supports tx-status report. Hence mac80211 should
>>> use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
>>> tx-frm.
>>>
>>> But then again: NullFunc status reporting via htt tx-frm was broken on
>>> 10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.
>>>
>>> This problem has been effectively obscured on stock 10.1 by the
>>> offloaded beacon miss.
>>
>>
>> For what it's worth, I looked at the 4.0.4 ath10k yesterday, and it appears
>> it
>> ignores the message that the 10.1 firmware sends when beacon loss happens
>> anyway.  Maybe I misread the firmware code..it's a pile of indirection.
>>
>> Do you know how the firmware is supposed to signal beacon loss to
>> the host (from the host's perspective).
> 
> Normally driver would advertise IEEE80211_HW_CONNECTION_MONITOR
> to disable mac80211 from tracking connection. and driver should call
> ieee80211_beacon_loss up on receiving beacon loss event from FW
> which triggers disconnection in mac80211.


I do not see any calls to beacon_loss() in the ath10k driver,
so probably that firmware feature is not just fully wired up
to the driver.  Just as well since that firmware feature is
disabled in my (-diet variant) firmware entirely.

Thanks,
Ben


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Question on beacon-miss offloading.

[Ben Greear]

On 06/11/2015 11:03 PM, Michal Kazior wrote:
> On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
>> On 06/11/2015 02:07 PM, Ben Greear wrote:
>>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>>> to save space and because it will not work with lots of virtual
>>> stations.
>>>
>>> But, it must be that I need some way to tell the stack that this
>>> feature is not enabled, because when suddenly kill my AP, then
>>> the ath10k station connected to it shows endless 'beacon loss' events
>>> in 'iw events' output, but it never actually loses connection.
>>>
>>> Stock firmware works fine, so probably I just need to disable
>>> some feature flag when registering the ath10k hardware
>>> when using CT firmware.
>>>
>>> With stock firmware, I see a quick dissassociation due to inactivity.
>>>
>>> I am having poor luck finding how a driver tells the stack
>>> it has beacon miss offload or not, so, does anyone know how
>>> this is controlled?
>>
>> I still am not sure why stock firmware works, but it appears
>> the reason mine is failing is that the ACK status for mgt frames
>> is always set to TRUE since the ath10k wmi-mgt-tx API is so
>> lame.  So, mac80211 does a probe, ath10k lies and says it was
>> acked, and mac80211 then things all is well for another few
>> seconds.
> 
> mac80211 shouldn't do a Probe Req to an AP on beacon loss because
> ath10k advertises it supports tx-status report. Hence mac80211 should
> use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
> tx-frm.
> 
> But then again: NullFunc status reporting via htt tx-frm was broken on
> 10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.
> 
> This problem has been effectively obscured on stock 10.1 by the
> offloaded beacon miss.

Thanks for the hint.  I was able to fix my firmware to properly
return htt tx status, and now it appears to work properly.

A quick throughput test works as well, so hopefully no regressions.

I guess the NulFunc related comment is incorrect for 10.1 stock firmware?

Maybe some others?

static void ath10k_tx_htt(struct ath10k *ar, struct sk_buff *skb)
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
	int ret = 0;

	if (ar->htt.target_version_major >= 3) {
		/* Since HTT 3.0 there is no separate mgmt tx command */
		ret = ath10k_htt_tx(&ar->htt, skb);
		goto exit;
	}

	if (ieee80211_is_mgmt(hdr->frame_control)) {
		if (test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
			     ar->fw_features)) {
			if (skb_queue_len(&ar->wmi_mgmt_tx_queue) >=
			    ATH10K_MAX_NUM_MGMT_PENDING) {
				ath10k_warn(ar, "reached WMI management transmit queue limit\n");
				ret = -EBUSY;
				goto exit;
			}

			skb_queue_tail(&ar->wmi_mgmt_tx_queue, skb);
			ieee80211_queue_work(ar->hw, &ar->wmi_mgmt_tx_work);
		} else {
			ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
		}
	} else if (!test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
			     ar->fw_features) &&
		   ieee80211_is_nullfunc(hdr->frame_control)) {
		/* FW does not report tx status properly for NullFunc frames
		 * unless they are sent through mgmt tx path. mac80211 sends
		 * those frames when it detects link/beacon loss and depends
		 * on the tx status to be correct. */
		ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
	} else {
		ret = ath10k_htt_tx(&ar->htt, skb);
	}


Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Question on beacon-miss offloading.

[Michal Kazior]

On 12 June 2015 at 17:37, Ben Greear <greearb@candelatech.com> wrote:
> On 06/11/2015 11:03 PM, Michal Kazior wrote:
>> On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
>>> On 06/11/2015 02:07 PM, Ben Greear wrote:
>>>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>>>> to save space and because it will not work with lots of virtual
>>>> stations.
>>>>
>>>> But, it must be that I need some way to tell the stack that this
>>>> feature is not enabled, because when suddenly kill my AP, then
>>>> the ath10k station connected to it shows endless 'beacon loss' events
>>>> in 'iw events' output, but it never actually loses connection.
>>>>
>>>> Stock firmware works fine, so probably I just need to disable
>>>> some feature flag when registering the ath10k hardware
>>>> when using CT firmware.
>>>>
>>>> With stock firmware, I see a quick dissassociation due to inactivity.
>>>>
>>>> I am having poor luck finding how a driver tells the stack
>>>> it has beacon miss offload or not, so, does anyone know how
>>>> this is controlled?
>>>
>>> I still am not sure why stock firmware works, but it appears
>>> the reason mine is failing is that the ACK status for mgt frames
>>> is always set to TRUE since the ath10k wmi-mgt-tx API is so
>>> lame.  So, mac80211 does a probe, ath10k lies and says it was
>>> acked, and mac80211 then things all is well for another few
>>> seconds.
>>
>> mac80211 shouldn't do a Probe Req to an AP on beacon loss because
>> ath10k advertises it supports tx-status report. Hence mac80211 should
>> use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
>> tx-frm.
>>
>> But then again: NullFunc status reporting via htt tx-frm was broken on
>> 10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.
>>
>> This problem has been effectively obscured on stock 10.1 by the
>> offloaded beacon miss.
>
> Thanks for the hint.  I was able to fix my firmware to properly
> return htt tx status, and now it appears to work properly.
>
> A quick throughput test works as well, so hopefully no regressions.
>
> I guess the NulFunc related comment is incorrect for 10.1 stock firmware?
>
> Maybe some others?
>
> static void ath10k_tx_htt(struct ath10k *ar, struct sk_buff *skb)
> {
>         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
>         int ret = 0;
>
>         if (ar->htt.target_version_major >= 3) {
>                 /* Since HTT 3.0 there is no separate mgmt tx command */
>                 ret = ath10k_htt_tx(&ar->htt, skb);
>                 goto exit;
>         }
>
>         if (ieee80211_is_mgmt(hdr->frame_control)) {
>                 if (test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
>                              ar->fw_features)) {
>                         if (skb_queue_len(&ar->wmi_mgmt_tx_queue) >=
>                             ATH10K_MAX_NUM_MGMT_PENDING) {
>                                 ath10k_warn(ar, "reached WMI management transmit queue limit\n");
>                                 ret = -EBUSY;
>                                 goto exit;
>                         }
>
>                         skb_queue_tail(&ar->wmi_mgmt_tx_queue, skb);
>                         ieee80211_queue_work(ar->hw, &ar->wmi_mgmt_tx_work);
>                 } else {
>                         ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
>                 }
>         } else if (!test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
>                              ar->fw_features) &&
>                    ieee80211_is_nullfunc(hdr->frame_control)) {
>                 /* FW does not report tx status properly for NullFunc frames
>                  * unless they are sent through mgmt tx path. mac80211 sends
>                  * those frames when it detects link/beacon loss and depends
>                  * on the tx status to be correct. */
>                 ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
>         } else {
>                 ret = ath10k_htt_tx(&ar->htt, skb);
>         }

The NullFunc workaround was originally done for 999.999.0.636 but
should be true for 10.1 as well with the sole exception the latter
doesn't have htt-mgmt-tx to workaround the problem.


Michał

Re: Question on beacon-miss offloading.

[Ben Greear]

On 06/14/2015 10:36 PM, Michal Kazior wrote:
> On 12 June 2015 at 17:37, Ben Greear <greearb@candelatech.com> wrote:
>> On 06/11/2015 11:03 PM, Michal Kazior wrote:
>>> On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
>>>> On 06/11/2015 02:07 PM, Ben Greear wrote:
>>>>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>>>>> to save space and because it will not work with lots of virtual
>>>>> stations.
>>>>>
>>>>> But, it must be that I need some way to tell the stack that this
>>>>> feature is not enabled, because when suddenly kill my AP, then
>>>>> the ath10k station connected to it shows endless 'beacon loss' events
>>>>> in 'iw events' output, but it never actually loses connection.
>>>>>
>>>>> Stock firmware works fine, so probably I just need to disable
>>>>> some feature flag when registering the ath10k hardware
>>>>> when using CT firmware.
>>>>>
>>>>> With stock firmware, I see a quick dissassociation due to inactivity.
>>>>>
>>>>> I am having poor luck finding how a driver tells the stack
>>>>> it has beacon miss offload or not, so, does anyone know how
>>>>> this is controlled?
>>>>
>>>> I still am not sure why stock firmware works, but it appears
>>>> the reason mine is failing is that the ACK status for mgt frames
>>>> is always set to TRUE since the ath10k wmi-mgt-tx API is so
>>>> lame.  So, mac80211 does a probe, ath10k lies and says it was
>>>> acked, and mac80211 then things all is well for another few
>>>> seconds.
>>>
>>> mac80211 shouldn't do a Probe Req to an AP on beacon loss because
>>> ath10k advertises it supports tx-status report. Hence mac80211 should
>>> use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
>>> tx-frm.
>>>
>>> But then again: NullFunc status reporting via htt tx-frm was broken on
>>> 10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.
>>>
>>> This problem has been effectively obscured on stock 10.1 by the
>>> offloaded beacon miss.
>>
>> Thanks for the hint.  I was able to fix my firmware to properly
>> return htt tx status, and now it appears to work properly.
>>
>> A quick throughput test works as well, so hopefully no regressions.
>>
>> I guess the NulFunc related comment is incorrect for 10.1 stock firmware?
>>
>> Maybe some others?
>>
>> static void ath10k_tx_htt(struct ath10k *ar, struct sk_buff *skb)
>> {
>>         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
>>         int ret = 0;
>>
>>         if (ar->htt.target_version_major >= 3) {
>>                 /* Since HTT 3.0 there is no separate mgmt tx command */
>>                 ret = ath10k_htt_tx(&ar->htt, skb);
>>                 goto exit;
>>         }
>>
>>         if (ieee80211_is_mgmt(hdr->frame_control)) {
>>                 if (test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
>>                              ar->fw_features)) {
>>                         if (skb_queue_len(&ar->wmi_mgmt_tx_queue) >=
>>                             ATH10K_MAX_NUM_MGMT_PENDING) {
>>                                 ath10k_warn(ar, "reached WMI management transmit queue limit\n");
>>                                 ret = -EBUSY;
>>                                 goto exit;
>>                         }
>>
>>                         skb_queue_tail(&ar->wmi_mgmt_tx_queue, skb);
>>                         ieee80211_queue_work(ar->hw, &ar->wmi_mgmt_tx_work);
>>                 } else {
>>                         ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
>>                 }
>>         } else if (!test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
>>                              ar->fw_features) &&
>>                    ieee80211_is_nullfunc(hdr->frame_control)) {
>>                 /* FW does not report tx status properly for NullFunc frames
>>                  * unless they are sent through mgmt tx path. mac80211 sends
>>                  * those frames when it detects link/beacon loss and depends
>>                  * on the tx status to be correct. */
>>                 ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
>>         } else {
>>                 ret = ath10k_htt_tx(&ar->htt, skb);
>>         }
> 
> The NullFunc workaround was originally done for 999.999.0.636 but
> should be true for 10.1 as well with the sole exception the latter
> doesn't have htt-mgmt-tx to workaround the problem.

Is it correct to say that this logic is completely broken for stock 10.1 firmware
because null-func frames are not management frames, so the packet goes out the
ath10k_htt_mgmt_tx call, and stock 10.1 does not properly do tx status
for htt-tx frames?


And slightly different question:  Once I put in proper htt ACK reporting into
my firmware, I notice that stations often loose connectivity when they are
idle.  I captured a sniff, and it appears the null-func packets are sent,
but the header is not requesting an explicit ACK, and the AP does not ACK it,
so connection is lost.

I guess that the null-func frames should be requesting explicit ACK?

Thanks,
Ben



-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Question on beacon-miss offloading.

[Ben Greear]

On 06/15/2015 08:35 AM, Ben Greear wrote:
> On 06/14/2015 10:36 PM, Michal Kazior wrote:
>> On 12 June 2015 at 17:37, Ben Greear <greearb@candelatech.com> wrote:
>>> On 06/11/2015 11:03 PM, Michal Kazior wrote:
>>>> On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
>>>>> On 06/11/2015 02:07 PM, Ben Greear wrote:
>>>>>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>>>>>> to save space and because it will not work with lots of virtual
>>>>>> stations.
>>>>>>
>>>>>> But, it must be that I need some way to tell the stack that this
>>>>>> feature is not enabled, because when suddenly kill my AP, then
>>>>>> the ath10k station connected to it shows endless 'beacon loss' events
>>>>>> in 'iw events' output, but it never actually loses connection.
>>>>>>
>>>>>> Stock firmware works fine, so probably I just need to disable
>>>>>> some feature flag when registering the ath10k hardware
>>>>>> when using CT firmware.
>>>>>>
>>>>>> With stock firmware, I see a quick dissassociation due to inactivity.
>>>>>>
>>>>>> I am having poor luck finding how a driver tells the stack
>>>>>> it has beacon miss offload or not, so, does anyone know how
>>>>>> this is controlled?
>>>>>
>>>>> I still am not sure why stock firmware works, but it appears
>>>>> the reason mine is failing is that the ACK status for mgt frames
>>>>> is always set to TRUE since the ath10k wmi-mgt-tx API is so
>>>>> lame.  So, mac80211 does a probe, ath10k lies and says it was
>>>>> acked, and mac80211 then things all is well for another few
>>>>> seconds.
>>>>
>>>> mac80211 shouldn't do a Probe Req to an AP on beacon loss because
>>>> ath10k advertises it supports tx-status report. Hence mac80211 should
>>>> use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
>>>> tx-frm.
>>>>
>>>> But then again: NullFunc status reporting via htt tx-frm was broken on
>>>> 10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.
>>>>
>>>> This problem has been effectively obscured on stock 10.1 by the
>>>> offloaded beacon miss.
>>>
>>> Thanks for the hint.  I was able to fix my firmware to properly
>>> return htt tx status, and now it appears to work properly.
>>>
>>> A quick throughput test works as well, so hopefully no regressions.
>>>
>>> I guess the NulFunc related comment is incorrect for 10.1 stock firmware?
>>>
>>> Maybe some others?
>>>
>>> static void ath10k_tx_htt(struct ath10k *ar, struct sk_buff *skb)
>>> {
>>>         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
>>>         int ret = 0;
>>>
>>>         if (ar->htt.target_version_major >= 3) {
>>>                 /* Since HTT 3.0 there is no separate mgmt tx command */
>>>                 ret = ath10k_htt_tx(&ar->htt, skb);
>>>                 goto exit;
>>>         }
>>>
>>>         if (ieee80211_is_mgmt(hdr->frame_control)) {
>>>                 if (test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
>>>                              ar->fw_features)) {
>>>                         if (skb_queue_len(&ar->wmi_mgmt_tx_queue) >=
>>>                             ATH10K_MAX_NUM_MGMT_PENDING) {
>>>                                 ath10k_warn(ar, "reached WMI management transmit queue limit\n");
>>>                                 ret = -EBUSY;
>>>                                 goto exit;
>>>                         }
>>>
>>>                         skb_queue_tail(&ar->wmi_mgmt_tx_queue, skb);
>>>                         ieee80211_queue_work(ar->hw, &ar->wmi_mgmt_tx_work);
>>>                 } else {
>>>                         ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
>>>                 }
>>>         } else if (!test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
>>>                              ar->fw_features) &&
>>>                    ieee80211_is_nullfunc(hdr->frame_control)) {
>>>                 /* FW does not report tx status properly for NullFunc frames
>>>                  * unless they are sent through mgmt tx path. mac80211 sends
>>>                  * those frames when it detects link/beacon loss and depends
>>>                  * on the tx status to be correct. */
>>>                 ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
>>>         } else {
>>>                 ret = ath10k_htt_tx(&ar->htt, skb);
>>>         }
>>
>> The NullFunc workaround was originally done for 999.999.0.636 but
>> should be true for 10.1 as well with the sole exception the latter
>> doesn't have htt-mgmt-tx to workaround the problem.
> 
> Is it correct to say that this logic is completely broken for stock 10.1 firmware
> because null-func frames are not management frames, so the packet goes out the
> ath10k_htt_mgmt_tx call, and stock 10.1 does not properly do tx status
> for htt-tx frames?
> 
> 
> And slightly different question:  Once I put in proper htt ACK reporting into
> my firmware, I notice that stations often loose connectivity when they are
> idle.  I captured a sniff, and it appears the null-func packets are sent,
> but the header is not requesting an explicit ACK, and the AP does not ACK it,
> so connection is lost.
> 
> I guess that the null-func frames should be requesting explicit ACK?

This patch below (with firmware fix to make it actually pay attention
to this special TID in station mode), fixes the null-func to be non-qos
frames and get immediate ack.  This in turn seems to fix the disconnect
issue I was facing, though I need to test some more to be sure.

This seem reasonable, maybe even for upstream?

[greearb@ben-dt2 ath10k]$ git diff
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 6ca48e3..610447e 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -2213,6 +2213,9 @@ static u8 ath10k_tx_h_get_tid(struct ieee80211_hdr *hdr)
        if (ieee80211_is_mgmt(hdr->frame_control))
                return HTT_DATA_TX_EXT_TID_MGMT;

+       if (ieee80211_is_nullfunc(hdr->frame_control))
+               return HTT_DATA_TX_EXT_TID_NON_QOS_MCAST_BCAST;
+
        if (!ieee80211_is_data_qos(hdr->frame_control))
                return HTT_DATA_TX_EXT_TID_NON_QOS_MCAST_BCAST;


Thanks,
Ben



-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Question on beacon-miss offloading.

[Michal Kazior]

On 15 June 2015 at 21:45, Ben Greear <greearb@candelatech.com> wrote:
> On 06/15/2015 08:35 AM, Ben Greear wrote:
>> On 06/14/2015 10:36 PM, Michal Kazior wrote:
>>> On 12 June 2015 at 17:37, Ben Greear <greearb@candelatech.com> wrote:
>>>> On 06/11/2015 11:03 PM, Michal Kazior wrote:
>>>>> On 12 June 2015 at 01:38, Ben Greear <greearb@candelatech.com> wrote:
>>>>>> On 06/11/2015 02:07 PM, Ben Greear wrote:
>>>>>>> In my ath10k CT firmware, I am disabling the beacon-miss offloading
>>>>>>> to save space and because it will not work with lots of virtual
>>>>>>> stations.
>>>>>>>
>>>>>>> But, it must be that I need some way to tell the stack that this
>>>>>>> feature is not enabled, because when suddenly kill my AP, then
>>>>>>> the ath10k station connected to it shows endless 'beacon loss' events
>>>>>>> in 'iw events' output, but it never actually loses connection.
>>>>>>>
>>>>>>> Stock firmware works fine, so probably I just need to disable
>>>>>>> some feature flag when registering the ath10k hardware
>>>>>>> when using CT firmware.
>>>>>>>
>>>>>>> With stock firmware, I see a quick dissassociation due to inactivity.
>>>>>>>
>>>>>>> I am having poor luck finding how a driver tells the stack
>>>>>>> it has beacon miss offload or not, so, does anyone know how
>>>>>>> this is controlled?
>>>>>>
>>>>>> I still am not sure why stock firmware works, but it appears
>>>>>> the reason mine is failing is that the ACK status for mgt frames
>>>>>> is always set to TRUE since the ath10k wmi-mgt-tx API is so
>>>>>> lame.  So, mac80211 does a probe, ath10k lies and says it was
>>>>>> acked, and mac80211 then things all is well for another few
>>>>>> seconds.
>>>>>
>>>>> mac80211 shouldn't do a Probe Req to an AP on beacon loss because
>>>>> ath10k advertises it supports tx-status report. Hence mac80211 should
>>>>> use NullFunc frames which shouldn't go through wmi-mgmt-tx but htt
>>>>> tx-frm.
>>>>>
>>>>> But then again: NullFunc status reporting via htt tx-frm was broken on
>>>>> 10.1 if memory serves right. I believe it was fixed in 10.2 or 10.2.4.
>>>>>
>>>>> This problem has been effectively obscured on stock 10.1 by the
>>>>> offloaded beacon miss.
>>>>
>>>> Thanks for the hint.  I was able to fix my firmware to properly
>>>> return htt tx status, and now it appears to work properly.
>>>>
>>>> A quick throughput test works as well, so hopefully no regressions.
>>>>
>>>> I guess the NulFunc related comment is incorrect for 10.1 stock firmware?
>>>>
>>>> Maybe some others?
>>>>
>>>> static void ath10k_tx_htt(struct ath10k *ar, struct sk_buff *skb)
>>>> {
>>>>         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
>>>>         int ret = 0;
>>>>
>>>>         if (ar->htt.target_version_major >= 3) {
>>>>                 /* Since HTT 3.0 there is no separate mgmt tx command */
>>>>                 ret = ath10k_htt_tx(&ar->htt, skb);
>>>>                 goto exit;
>>>>         }
>>>>
>>>>         if (ieee80211_is_mgmt(hdr->frame_control)) {
>>>>                 if (test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
>>>>                              ar->fw_features)) {
>>>>                         if (skb_queue_len(&ar->wmi_mgmt_tx_queue) >=
>>>>                             ATH10K_MAX_NUM_MGMT_PENDING) {
>>>>                                 ath10k_warn(ar, "reached WMI management transmit queue limit\n");
>>>>                                 ret = -EBUSY;
>>>>                                 goto exit;
>>>>                         }
>>>>
>>>>                         skb_queue_tail(&ar->wmi_mgmt_tx_queue, skb);
>>>>                         ieee80211_queue_work(ar->hw, &ar->wmi_mgmt_tx_work);
>>>>                 } else {
>>>>                         ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
>>>>                 }
>>>>         } else if (!test_bit(ATH10K_FW_FEATURE_HAS_WMI_MGMT_TX,
>>>>                              ar->fw_features) &&
>>>>                    ieee80211_is_nullfunc(hdr->frame_control)) {
>>>>                 /* FW does not report tx status properly for NullFunc frames
>>>>                  * unless they are sent through mgmt tx path. mac80211 sends
>>>>                  * those frames when it detects link/beacon loss and depends
>>>>                  * on the tx status to be correct. */
>>>>                 ret = ath10k_htt_mgmt_tx(&ar->htt, skb);
>>>>         } else {
>>>>                 ret = ath10k_htt_tx(&ar->htt, skb);
>>>>         }
>>>
>>> The NullFunc workaround was originally done for 999.999.0.636 but
>>> should be true for 10.1 as well with the sole exception the latter
>>> doesn't have htt-mgmt-tx to workaround the problem.
>>
>> Is it correct to say that this logic is completely broken for stock 10.1 firmware
>> because null-func frames are not management frames, so the packet goes out the
>> ath10k_htt_mgmt_tx call, and stock 10.1 does not properly do tx status
>> for htt-tx frames?

The has-wmi-mgmt-tx was originally designed to identify FW supporting
htt-mgmt-tx. It ended up to be used (implicitly) as a part of the
NullFunc workaround.

Hmm.. I guess it's not really ideal now because latest 10.2.4 FW which
supports htt-mgmt-tx doesn't need the workaround (htt-tx report
correct tx-status for NullFuncs)..


>> And slightly different question:  Once I put in proper htt ACK reporting into
>> my firmware, I notice that stations often loose connectivity when they are
>> idle.  I captured a sniff, and it appears the null-func packets are sent,
>> but the header is not requesting an explicit ACK, and the AP does not ACK it,
>> so connection is lost.
>>
>> I guess that the null-func frames should be requesting explicit ACK?
>
> This patch below (with firmware fix to make it actually pay attention
> to this special TID in station mode), fixes the null-func to be non-qos
> frames and get immediate ack.  This in turn seems to fix the disconnect
> issue I was facing, though I need to test some more to be sure.
>
> This seem reasonable, maybe even for upstream?
>
> [greearb@ben-dt2 ath10k]$ git diff
> diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
> index 6ca48e3..610447e 100644
> --- a/drivers/net/wireless/ath/ath10k/mac.c
> +++ b/drivers/net/wireless/ath/ath10k/mac.c
> @@ -2213,6 +2213,9 @@ static u8 ath10k_tx_h_get_tid(struct ieee80211_hdr *hdr)
>         if (ieee80211_is_mgmt(hdr->frame_control))
>                 return HTT_DATA_TX_EXT_TID_MGMT;
>
> +       if (ieee80211_is_nullfunc(hdr->frame_control))
> +               return HTT_DATA_TX_EXT_TID_NON_QOS_MCAST_BCAST;
> +

That's weird.. QoS NullFunc frames are already converted to non-QoS
frames, see ath10k_tx_h_nwifi():

        /* Some firmware revisions don't handle sending QoS NullFunc well.
         * These frames are mainly used for CQM purposes so it doesn't really
         * matter whether QoS NullFunc or NullFunc are sent.
         */
        hdr = (void *)skb->data;
        if (ieee80211_is_qos_nullfunc(hdr->frame_control))
                cb->htt.tid = HTT_DATA_TX_EXT_TID_NON_QOS_MCAST_BCAST;

Or is it that ath10k_tx_h_get_tid() has a bug that ends up assigning
an invalid tid for non-QoS NullFunc frames? If so I guess your patch
would be okay with some comments/commit-log explaining why/what was
wrong.


Michał

Re: Question on beacon-miss offloading.

[Ben Greear]

On 06/15/2015 10:29 PM, Michal Kazior wrote:

>> This patch below (with firmware fix to make it actually pay attention
>> to this special TID in station mode), fixes the null-func to be non-qos
>> frames and get immediate ack.  This in turn seems to fix the disconnect
>> issue I was facing, though I need to test some more to be sure.
>>
>> This seem reasonable, maybe even for upstream?
>>
>> [greearb@ben-dt2 ath10k]$ git diff
>> diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
>> index 6ca48e3..610447e 100644
>> --- a/drivers/net/wireless/ath/ath10k/mac.c
>> +++ b/drivers/net/wireless/ath/ath10k/mac.c
>> @@ -2213,6 +2213,9 @@ static u8 ath10k_tx_h_get_tid(struct ieee80211_hdr *hdr)
>>         if (ieee80211_is_mgmt(hdr->frame_control))
>>                 return HTT_DATA_TX_EXT_TID_MGMT;
>>
>> +       if (ieee80211_is_nullfunc(hdr->frame_control))
>> +               return HTT_DATA_TX_EXT_TID_NON_QOS_MCAST_BCAST;
>> +
> 
> That's weird.. QoS NullFunc frames are already converted to non-QoS
> frames, see ath10k_tx_h_nwifi():

True, but the 4.0.4 kernel sends down non-qos null-func frames as far
as I can tell, at least when doing connection probing.

In my case, my kernel was sending non-qos nullfunc frame to firmware, but then
firmware stuck it on BE queue and made it QoS.

>         /* Some firmware revisions don't handle sending QoS NullFunc well.
>          * These frames are mainly used for CQM purposes so it doesn't really
>          * matter whether QoS NullFunc or NullFunc are sent.
>          */
>         hdr = (void *)skb->data;
>         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
>                 cb->htt.tid = HTT_DATA_TX_EXT_TID_NON_QOS_MCAST_BCAST;
> 
> Or is it that ath10k_tx_h_get_tid() has a bug that ends up assigning
> an invalid tid for non-QoS NullFunc frames? If so I guess your patch
> would be okay with some comments/commit-log explaining why/what was
> wrong.

I tried very recent upstream ath kernel, and stock firmware-2.bin, and it
seems to generate null-func frames fine.  I'll go back at look at my
recent FW and kernel changes in more detail now that I understand the problem
better and see if I can figure out what is going on...

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Question on beacon-miss offloading.

[Ben Greear]

On 06/16/2015 02:55 PM, Ben Greear wrote:
> On 06/15/2015 10:29 PM, Michal Kazior wrote:
> 
>>> This patch below (with firmware fix to make it actually pay attention
>>> to this special TID in station mode), fixes the null-func to be non-qos
>>> frames and get immediate ack.  This in turn seems to fix the disconnect
>>> issue I was facing, though I need to test some more to be sure.
>>>
>>> This seem reasonable, maybe even for upstream?
>>>
>>> [greearb@ben-dt2 ath10k]$ git diff
>>> diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
>>> index 6ca48e3..610447e 100644
>>> --- a/drivers/net/wireless/ath/ath10k/mac.c
>>> +++ b/drivers/net/wireless/ath/ath10k/mac.c
>>> @@ -2213,6 +2213,9 @@ static u8 ath10k_tx_h_get_tid(struct ieee80211_hdr *hdr)
>>>         if (ieee80211_is_mgmt(hdr->frame_control))
>>>                 return HTT_DATA_TX_EXT_TID_MGMT;
>>>
>>> +       if (ieee80211_is_nullfunc(hdr->frame_control))
>>> +               return HTT_DATA_TX_EXT_TID_NON_QOS_MCAST_BCAST;
>>> +
>>
>> That's weird.. QoS NullFunc frames are already converted to non-QoS
>> frames, see ath10k_tx_h_nwifi():
> 
> True, but the 4.0.4 kernel sends down non-qos null-func frames as far
> as I can tell, at least when doing connection probing.
> 
> In my case, my kernel was sending non-qos nullfunc frame to firmware, but then
> firmware stuck it on BE queue and made it QoS.

Stock 4.0.4 and stock firmware-2.bin have the same 'nullfunc sent as qos and no immediate ack' bug,
so it must be something that was fixed or changed between 4.0.4 and the 4.1.x ath tree.

Thanks,
Ben

>>         /* Some firmware revisions don't handle sending QoS NullFunc well.
>>          * These frames are mainly used for CQM purposes so it doesn't really
>>          * matter whether QoS NullFunc or NullFunc are sent.
>>          */
>>         hdr = (void *)skb->data;
>>         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
>>                 cb->htt.tid = HTT_DATA_TX_EXT_TID_NON_QOS_MCAST_BCAST;
>>
>> Or is it that ath10k_tx_h_get_tid() has a bug that ends up assigning
>> an invalid tid for non-QoS NullFunc frames? If so I guess your patch
>> would be okay with some comments/commit-log explaining why/what was
>> wrong.
> 
> I tried very recent upstream ath kernel, and stock firmware-2.bin, and it
> seems to generate null-func frames fine.  I'll go back at look at my
> recent FW and kernel changes in more detail now that I understand the problem
> better and see if I can figure out what is going on...
> 
> Thanks,
> Ben
> 


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com