No probe response from AP after 500ms, disconnecting.

No probe response from AP after 500ms, disconnecting.

[Peter Stuge]

(linux-wireless posters, please Cc me since I am only subscribed to
ath9k-devel.)


Hello,

I get the above error (and thus loss of connectivity) using
wireless-testing/master as of Dec 13.

phy0: Atheros AR5416 MAC/BB Rev:2 AR5133 RF Rev:81: mem=0xf8320000, irq=21

I've previously posted various other info starting at
http://bugzilla.kernel.org/show_bug.cgi?id=14664#c1
and
http://bugzilla.kernel.org/show_bug.cgi?id=14267#c53

I recently installed this card in my laptop. I had drm-intel.git at
2.6.32-rc6 at that time and after seeing the error there I merged
wireless-testing/master since I thought that was the most recent
ath9k source. I'm happy to switch to something else if that helps,
just tell me where to get it.

I searched for a bug to add my information and find hints. I found
the above bugs which describe this very symptom, but Luis asked me to
move over to mailing lists since I see this also in wireless-testing.

I think I've tried all suggestions in bug 14267, but the issue
remains.

Manually disabling power management for the interface (iwconfig eth1
power off) makes it much more stable but I've still seen the error
twice. The first time after about a day and then again after a few
hours. I've been running with power management off since then, a
couple of days, so far without seeing the problem again.

My attachment in bug 14267 is a log from the first occurence but it
does not have very many messages leading up to the error. I also have
a longer debug log from the second time it happened, with about 5000
lines before the disconnect: http://stuge.se/ath9kdisconn.txt


I have applied these 6 patches posted by Sujith this week:

ath9k: Fix bug in assigning sequence number
ath9k: Clarify Interrupt mitigation
ath9k: Stop ANI when doing a reset
ath9k: Remove ANI lock
ath9k: Fix TX poll routine
ath9k: Fix TX queue draining

I then enabled power management and was disconnected after the
interface had been up for no more than a few minutes. I am now
running with PM off again, so that I can use the interface. :)


Luis R. Rodriguez wrote:
> > > The fix on 2.6.32 which should help AR5416 (so far concrete
> > > device with issues) is to disable PS by default.
..
> > This worked well for me during brief testing with the -rc6 kernel. I
> > then switched to wl-testing to be up to date.
> 
> That's indeed a good move to test.

To clarify; I only tested with power management off on -rc6 for a few
minutes, and then I switched to the wireless-testing/master kernel
that I am running now.


> > The fix to disable by default is included in my kernel, and PS is
> > off. I still observe the problem,
> 
> Well so depending on the device you have you may need some patches
> which may or may not have been present on wireless-testing.

What exactly does "on wireless-testing" mean? Are they in the
ath9k-devel archive or the linux-wireless archive? I would prefer to
fetch from a git, but email works too. Are patches committed to a
branch on wireless-testing.git? Or is there an ath9k.git?


> Some recent fixes for ath9k on 2.6.32 and wireless-testing are
> important,

As I wrote in one bug comment; I was running a wireless-testing
kernel per commit c770b16cd572bd434f90794be03ae20f5974e6e9 from Dec
13, and I saw the issue twice also with power management disabled.

It seems to me (of course I don't know the internals though) that
power management is not the single factor in this issue.


> Sujith also posted some recent fixes. They don't all pertain to
> power save but some do.

I applied the above 6 patches from Sujith. It's difficult to know if
I got the ones you mean without a more specific description. :)

The patches posted by you to linux-wireless@ on 2009-12-16 are
included in my wireless-testing/master kernel already:

ath9k: Fix TX hang poll routine
commit 73803a9b535b76f36afba4881af22fe7b84f49c0
CommitDate: Fri Dec 4 16:12:31 2009 -0500

ath9k: fix processing of TX PS null data frames
commit 87340fcfc6ada956132878a72efdc75431a684b3
CommitDate: Fri Dec 4 16:15:41 2009 -0500

ath9k: Fix maximum tx fifo settings for single stream devices
commit 499e75e2c226aa49ba1e801462a0bee02756984a
CommitDate: Fri Dec 4 16:15:42 2009 -0500

ath9k: fix tx status reporting
commit e8c6342d989e241513baeba4b05a04b6b1f3bc8b
CommitDate: Mon Dec 7 17:05:40 2009 -0500

mac80211: Fix dynamic power save for scanning.
commit fba4a86f5b2652fac0c508968a3a4b4e03d6b661
CommitDate: Mon Dec 7 17:05:35 2009 -0500


> On your bug report you did not indicate if you tested 2.6.32 with
> the latest patches I had suggested to Justin.

I did not test them on top of the .32-rc6 kernel but again they're in
the current kernel and I still reproduce the issue quickly with power
management on, and have seen it twice with PM off.

So far I have not seen the issue with PM off and 6 above patches
applied, that is what I am running with right now and I'll let you
know what happens. (With PM on the issue is still frequent.)


> OK you also have an AR5416, which is the first 11n chipset
> generation for Atheros, the bug report was originally for AR9280.
> Justin also has an AR5416.
> 
> Lets make sure to keep these separate.

The failure mode is the same, AR9280 is PCIe, AR9220 may be too
uncommon to have any data points and I see the issue only very
infrequently with power management off on AR5416. I think all these
factors can support that it is a single issue. But they are in no way
conclusive! Hopefully it can be fixed somewhere so that there will be
more data.


> > Nod. Let's go. How can I help further?
> 
> Try sucking in Sujith's recent posted patches, although none of
> those are PS fixes,

Did I get the right ones?


> and you can also follow the instructions I gave Justin to help
> debug things.

I tried to do that already. The debug log I attached didn't have too
much info leading up to the disconnect though. Feel free to get the
longer one.

Is there anything else can I do?


//Peter

Re: [ath9k-devel] No probe response from AP after 500ms, disconnecting.

[Luis R. Rodriguez]

On Fri, Dec 18, 2009 at 03:57:08AM -0800, Peter Stuge wrote:
> (linux-wireless posters, please Cc me since I am only subscribed to
> ath9k-devel.)
> 
> 
> Hello,
> 
> I get the above error (and thus loss of connectivity) using
> wireless-testing/master as of Dec 13.
> 
> phy0: Atheros AR5416 MAC/BB Rev:2 AR5133 RF Rev:81: mem=0xf8320000, irq=21
> 
> I've previously posted various other info starting at
> http://bugzilla.kernel.org/show_bug.cgi?id=14664#c1
> and
> http://bugzilla.kernel.org/show_bug.cgi?id=14267#c53
> 
> I recently installed this card in my laptop. I had drm-intel.git at
> 2.6.32-rc6 at that time and after seeing the error there I merged
> wireless-testing/master since I thought that was the most recent
> ath9k source. I'm happy to switch to something else if that helps,
> just tell me where to get it.
> 
> I searched for a bug to add my information and find hints. I found
> the above bugs which describe this very symptom, but Luis asked me to
> move over to mailing lists since I see this also in wireless-testing.
> 
> I think I've tried all suggestions in bug 14267, but the issue
> remains.

This seems like your old comments from an old e-mail, but I guess you
include them since you now include linux-wireless.

> Manually disabling power management for the interface (iwconfig eth1
> power off) makes it much more stable but I've still seen the error
> twice. The first time after about a day and then again after a few
> hours. I've been running with power management off since then, a
> couple of days, so far without seeing the problem again.

Neat.

> My attachment in bug 14267 is a log from the first occurence but it
> does not have very many messages leading up to the error. I also have
> a longer debug log from the second time it happened, with about 5000
> lines before the disconnect: http://stuge.se/ath9kdisconn.txt
> 
> 
> I have applied these 6 patches posted by Sujith this week:
> 
> ath9k: Fix bug in assigning sequence number
> ath9k: Clarify Interrupt mitigation
> ath9k: Stop ANI when doing a reset
> ath9k: Remove ANI lock
> ath9k: Fix TX poll routine
> ath9k: Fix TX queue draining
> 
> I then enabled power management and was disconnected after the
> interface had been up for no more than a few minutes. I am now
> running with PM off again, so that I can use the interface. :)

Thanks for testing.

> Luis R. Rodriguez wrote:
> > > > The fix on 2.6.32 which should help AR5416 (so far concrete
> > > > device with issues) is to disable PS by default.
> ..
> > > This worked well for me during brief testing with the -rc6 kernel. I
> > > then switched to wl-testing to be up to date.
> >
> > That's indeed a good move to test.
> 
> To clarify; I only tested with power management off on -rc6 for a few
> minutes, and then I switched to the wireless-testing/master kernel
> that I am running now.

Understood, thanks for the clarification.

> > > The fix to disable by default is included in my kernel, and PS is
> > > off. I still observe the problem,
> >
> > Well so depending on the device you have you may need some patches
> > which may or may not have been present on wireless-testing.
> 
> What exactly does "on wireless-testing" mean? Are they in the
> ath9k-devel archive or the linux-wireless archive? I would prefer to
> fetch from a git, but email works too. Are patches committed to a
> branch on wireless-testing.git? Or is there an ath9k.git?

Wireless-testing is that git tree you cloned. Bleedinge edge wireless
patches posted to linux-wireless get merged to there by John in
preparation for the next merge window.

> > Some recent fixes for ath9k on 2.6.32 and wireless-testing are
> > important,
> 
> As I wrote in one bug comment; I was running a wireless-testing
> kernel per commit c770b16cd572bd434f90794be03ae20f5974e6e9 from Dec
> 13, and I saw the issue twice also with power management disabled.
> 
> It seems to me (of course I don't know the internals though) that
> power management is not the single factor in this issue.

It should also be noted the issues are affecting AR5416 with PS enabled
by default, AR9280 and friends seem to be OK with the latest patches.

> > Sujith also posted some recent fixes. They don't all pertain to
> > power save but some do.
> 
> I applied the above 6 patches from Sujith. It's difficult to know if
> I got the ones you mean without a more specific description. :)
> 
> The patches posted by you to linux-wireless@ on 2009-12-16 are
> included in my wireless-testing/master kernel already:
> 
> ath9k: Fix TX hang poll routine
> commit 73803a9b535b76f36afba4881af22fe7b84f49c0
> CommitDate: Fri Dec 4 16:12:31 2009 -0500
> 
> ath9k: fix processing of TX PS null data frames
> commit 87340fcfc6ada956132878a72efdc75431a684b3
> CommitDate: Fri Dec 4 16:15:41 2009 -0500
> 
> ath9k: Fix maximum tx fifo settings for single stream devices
> commit 499e75e2c226aa49ba1e801462a0bee02756984a
> CommitDate: Fri Dec 4 16:15:42 2009 -0500
> 
> ath9k: fix tx status reporting
> commit e8c6342d989e241513baeba4b05a04b6b1f3bc8b
> CommitDate: Mon Dec 7 17:05:40 2009 -0500
> 
> mac80211: Fix dynamic power save for scanning.
> commit fba4a86f5b2652fac0c508968a3a4b4e03d6b661
> CommitDate: Mon Dec 7 17:05:35 2009 -0500

So these would apply to stable, but wireless-testing should have had
these already. The patche I was referring to from Sujith were posted
only to linux-wireless, these are now merged on wireless-testing.

> > On your bug report you did not indicate if you tested 2.6.32 with
> > the latest patches I had suggested to Justin.
> 
> I did not test them on top of the .32-rc6 kernel but again they're in
> the current kernel and I still reproduce the issue quickly with power
> management on, and have seen it twice with PM off.
> 
> So far I have not seen the issue with PM off and 6 above patches
> applied, that is what I am running with right now and I'll let you
> know what happens. (With PM on the issue is still frequent.)

OK so far this narrows down to a specific AR5416 issue with PM on
by default only.

> > OK you also have an AR5416, which is the first 11n chipset
> > generation for Atheros, the bug report was originally for AR9280.
> > Justin also has an AR5416.
> >
> > Lets make sure to keep these separate.
> 
> The failure mode is the same, AR9280 is PCIe, AR9220 may be too
> uncommon to have any data points and I see the issue only very
> infrequently with power management off on AR5416. I think all these
> factors can support that it is a single issue. But they are in no way
> conclusive! Hopefully it can be fixed somewhere so that there will be
> more data.

They are different hardware, newer hardware families (>= AR9280) are
single chip and quite a few changes went into them, so thinking of them
as equal would be wrong. They certain share a lot but for example the
radios are completely different. Now sure, the issue can be the similar
but it doesn't mean that it is not fixed for some chipsets, ignoring that
would be unfair for those users of the newer harware families.

> > > Nod. Let's go. How can I help further?
> >
> > Try sucking in Sujith's recent posted patches, although none of
> > those are PS fixes,
> 
> Did I get the right ones?

Those are indeed needed but Sujith posted some new patch fixes but
not related to PS. Some of these fixes are to be merged in the next
next 2.6.32.y so might as well go ahead and apply then if using stable
or even wireless-testing. So no, you mised them. Here they are:

http://marc.info/?l=linux-wireless&r=3&b=200912&w=2

Patchwork has them in git am'able form:

http://patchwork.kernel.org/project/linux-wireless/list/

> > and you can also follow the instructions I gave Justin to help
> > debug things.
> 
> I tried to do that already. The debug log I attached didn't have too
> much info leading up to the disconnect though. Feel free to get the
> longer one.
> 
> Is there anything else can I do?

Try with the above, although I doubt they will help AR5416.

  Luis

Re: [ath9k-devel] No probe response from AP after 500ms, disconnecting.

[Peter Stuge]

Hi Luis,

Thanks for the reply!


Luis R. Rodriguez wrote:
> This seems like your old comments from an old e-mail, but I guess
> you include them since you now include linux-wireless.

Yeah, I tried to summarize previous and new findings for new readers.


> > Manually disabling power management for the interface (iwconfig eth1
> > power off) makes it much more stable but I've still seen the error
> > twice. The first time after about a day and then again after a few
> > hours. I've been running with power management off since then, a
> > couple of days, so far without seeing the problem again.
> 
> Neat.

Well, I am in no way convinced that the problem is gone just because
I haven't seen it for a few days. I haven't rebooted this machine
since the last issues, only unloaded/reloaded the ath modules after
each patch/compile cycle, that might matter too..


> > I have applied these 6 patches posted by Sujith this week:
> > 
> > ath9k: Fix bug in assigning sequence number
> > ath9k: Clarify Interrupt mitigation
> > ath9k: Stop ANI when doing a reset
> > ath9k: Remove ANI lock
> > ath9k: Fix TX poll routine
> > ath9k: Fix TX queue draining

..
> > I applied the above 6 patches from Sujith. It's difficult to know if
> > I got the ones you mean without a more specific description. :)
> > 
> > The patches posted by you to linux-wireless@ on 2009-12-16 are
> > included in my wireless-testing/master kernel already:
> > 
> > ath9k: Fix TX hang poll routine
..
> > ath9k: fix processing of TX PS null data frames
..
> > ath9k: Fix maximum tx fifo settings for single stream devices
..
> > ath9k: fix tx status reporting
..
> > mac80211: Fix dynamic power save for scanning.
> 
> So these would apply to stable, but wireless-testing should have had
> these already.

Right; "are included in my wireless-testing/master kernel already"..


> > So far I have not seen the issue with PM off and 6 above patches
> > applied, that is what I am running with right now and I'll let you
> > know what happens. (With PM on the issue is still frequent.)
> 
> OK so far this narrows down to a specific AR5416 issue with PM on
> by default only.

I'm not sure about "by default". The kernel I am running has the
workaround committed which disables PM by default. If I manually
enable PM I will quickly see the issue.


> They are different hardware, newer hardware families (>= AR9280)
> are single chip and quite a few changes went into them, so thinking
> of them as equal would be wrong.

Right, no, they are certainly not equal. But parts of them are - or
maybe more importantly, parts of the driver are.


> They certain share a lot but for example the radios are completely
> different.

Yeah - I imagine there were some changes when the radios went onto
the same chip.

I don't know if this problem lies closer to RF or Linux. Can we
narrow it down somehow?


> Now sure, the issue can be the similar but it doesn't mean that it
> is not fixed for some chipsets, ignoring that would be unfair for
> those users of the newer harware families.

Oh yes - I didn't mean that progressive patches should be blocked in
any way, but just to keep an open mind until the issue is completely
solved. :)


> > > Try sucking in Sujith's recent posted patches, although none of
> > > those are PS fixes,
> > 
> > Did I get the right ones?
> 
> Those are indeed needed but Sujith posted some new patch fixes but
> not related to PS. Some of these fixes are to be merged in the next
> next 2.6.32.y so might as well go ahead and apply then if using stable
> or even wireless-testing. So no, you mised them. Here they are:
> 
> http://marc.info/?l=linux-wireless&r=3&b=200912&w=2
> 
> Patchwork has them in git am'able form:
> 
> http://patchwork.kernel.org/project/linux-wireless/list/

The latest patches from Sujith are dated 2009-12-14 and are the ANI,
TX queue, TX hang, etc patches that I listed above saying that I had
applied them. They are in my running driver.


> > > and you can also follow the instructions I gave Justin to help
> > > debug things.
> > 
> > I tried to do that already. The debug log I attached didn't have too
> > much info leading up to the disconnect though. Feel free to get the
> > longer one.
> > 
> > Is there anything else can I do?
> 
> Try with the above, although I doubt they will help AR5416.

So what could give us more information? If the debug output is not
enough I'm happy to sprinkle printks over the driver in strategic
places, but I need some hints on where to do it.

What is the general operation of the driver? (I have some experience
with writing Linux drivers so feel free to get technical.) RX
descriptors and DMA? Is beacon reception special in any way from
reception of other packets? Would it be useful to try monitor mode
with PM enabled?

I am continuously using low TX and moderate RX bandwidth (internet
radio over a TCP VPN) - would it be helpful to load the card with
exclusively unidirectional transfers such as UDP, to see if the
problem becomes more or less frequent?

Although the issue can be seen as missing beacons maybe it is a
general problem with RX that is only visible in the log when the time
comes to expect a beacon?


Where to look further?


//Peter

Re: [ath9k-devel] No probe response from AP after 500ms, disconnecting.

[Vivek Natarajan]

On Sat, Dec 19, 2009 at 1:37 AM, Peter Stuge <peter@stuge.se> wrote:

> So what could give us more information? If the debug output is not
> enough I'm happy to sprinkle printks over the driver in strategic
> places, but I need some hints on where to do it.
>
> What is the general operation of the driver? (I have some experience
> with writing Linux drivers so feel free to get technical.) RX
> descriptors and DMA? Is beacon reception special in any way from
> reception of other packets? Would it be useful to try monitor mode
> with PM enabled?

If the issue is specific to AR5416 and power save, then the TIM_TIMER
interrupt might be causing the trouble. You can check whether any
ATH9K_INT_TIM_TIMER interrupt is received in the ath_isr when the
disconnection happens.
This is the hw timer used by the chip to wakeup for  every beacon listen
interval.

Vivek.