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From: Johan Hovold <johan@kernel.org>
To: Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
Cc: Johan Hovold <johan+linaro@kernel.org>,
	Kalle Valo <kvalo@kernel.org>,
	Jeff Johnson <quic_jjohnson@quicinc.com>,
	Bjorn Andersson <quic_bjorande@quicinc.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Revert "Revert "wifi: ath11k: Enable threaded NAPI""
Date: Wed, 9 Aug 2023 11:16:06 +0200	[thread overview]
Message-ID: <ZNNZVsFb3_Dt_NMb@hovoldconsulting.com> (raw)
In-Reply-To: <42f78c02-1ddc-cf1c-694f-abf9059dfb60@quicinc.com>

On Wed, Aug 09, 2023 at 02:32:37PM +0530, Manikanta Pubbisetty wrote:
> On 8/9/2023 1:04 PM, Johan Hovold wrote:
> > This reverts commit d265ebe41c911314bd273c218a37088835959fa1.
> > 
> > Disabling threaded NAPI causes the Lenovo ThinkPad X13s to hang (e.g. no
> > more interrupts received) almost immediately during RX.
> > 
> > Apparently something broke since commit 13aa2fb692d3 ("wifi: ath11k:
> > Enable threaded NAPI") so that a simple revert is no longer possible.
> > 
> 
> This is getting as weird as it would get :)
> 
> > As commit d265ebe41c91 ("Revert "wifi: ath11k: Enable threaded NAPI"")
> > does not address the underlying issue reported with QCN9074, it seems we
> > need to reenable threaded NAPI before fixing both bugs properly.
> > 
> 
> It seems that the revert has actually solved the issue reported with 
> QCN9074.
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=217536

Sure, but it's only a workaround as the underlying cause has not been
identified.

> We were trying to reproduce the problem on X86+QCN9074 (with threaded 
> NAPI) from quite some time, but there is no repro yet.
>
> Actually, enabling/disabling threaded NAPI is a simple affair; I'm 
> wondering to hear that interrupts are blocked due  to not having 
> threaded NAPI.

It sounds to me like the driver's locking is broken if moving to softirq
processing hangs the machine like this. But I have not had time to try
to try to track it down besides verifying that reenabling threaded NAPI
makes the problem go away.

> What is the chip that Lenovo Thinkpad X13s is having?

It's a WCN6855 (QCNFA765).

Johan

-- 
ath11k mailing list
ath11k@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/ath11k

WARNING: multiple messages have this Message-ID (diff)
From: Johan Hovold <johan@kernel.org>
To: Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
Cc: Johan Hovold <johan+linaro@kernel.org>,
	Kalle Valo <kvalo@kernel.org>,
	Jeff Johnson <quic_jjohnson@quicinc.com>,
	Bjorn Andersson <quic_bjorande@quicinc.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Revert "Revert "wifi: ath11k: Enable threaded NAPI""
Date: Wed, 9 Aug 2023 11:16:06 +0200	[thread overview]
Message-ID: <ZNNZVsFb3_Dt_NMb@hovoldconsulting.com> (raw)
In-Reply-To: <42f78c02-1ddc-cf1c-694f-abf9059dfb60@quicinc.com>

On Wed, Aug 09, 2023 at 02:32:37PM +0530, Manikanta Pubbisetty wrote:
> On 8/9/2023 1:04 PM, Johan Hovold wrote:
> > This reverts commit d265ebe41c911314bd273c218a37088835959fa1.
> > 
> > Disabling threaded NAPI causes the Lenovo ThinkPad X13s to hang (e.g. no
> > more interrupts received) almost immediately during RX.
> > 
> > Apparently something broke since commit 13aa2fb692d3 ("wifi: ath11k:
> > Enable threaded NAPI") so that a simple revert is no longer possible.
> > 
> 
> This is getting as weird as it would get :)
> 
> > As commit d265ebe41c91 ("Revert "wifi: ath11k: Enable threaded NAPI"")
> > does not address the underlying issue reported with QCN9074, it seems we
> > need to reenable threaded NAPI before fixing both bugs properly.
> > 
> 
> It seems that the revert has actually solved the issue reported with 
> QCN9074.
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=217536

Sure, but it's only a workaround as the underlying cause has not been
identified.

> We were trying to reproduce the problem on X86+QCN9074 (with threaded 
> NAPI) from quite some time, but there is no repro yet.
>
> Actually, enabling/disabling threaded NAPI is a simple affair; I'm 
> wondering to hear that interrupts are blocked due  to not having 
> threaded NAPI.

It sounds to me like the driver's locking is broken if moving to softirq
processing hangs the machine like this. But I have not had time to try
to try to track it down besides verifying that reenabling threaded NAPI
makes the problem go away.

> What is the chip that Lenovo Thinkpad X13s is having?

It's a WCN6855 (QCNFA765).

Johan

  reply	other threads:[~2023-08-09  9:16 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-09  7:34 [PATCH] Revert "Revert "wifi: ath11k: Enable threaded NAPI"" Johan Hovold
2023-08-09  7:34 ` Johan Hovold
2023-08-09  9:02 ` Manikanta Pubbisetty
2023-08-09  9:02   ` Manikanta Pubbisetty
2023-08-09  9:16   ` Johan Hovold [this message]
2023-08-09  9:16     ` Johan Hovold
2023-08-10  4:33     ` Manikanta Pubbisetty
2023-08-10  4:33       ` Manikanta Pubbisetty
2023-08-21 13:27       ` Johan Hovold
2023-08-21 13:27         ` Johan Hovold
2023-08-10  4:46     ` Manikanta Pubbisetty
2023-08-10  4:46       ` Manikanta Pubbisetty
2023-08-21 13:29       ` Johan Hovold
2023-08-21 13:29         ` Johan Hovold
2023-08-21 13:41 ` Johan Hovold
2023-08-21 13:41   ` Johan Hovold
2023-08-22 12:56   ` Kalle Valo
2023-08-22 12:56     ` Kalle Valo
2023-08-22 13:44     ` Johan Hovold
2023-08-22 13:44       ` Johan Hovold
2023-08-26 15:53       ` Johan Hovold
2023-08-26 15:53         ` Johan Hovold
2023-08-29 11:47         ` Kalle Valo
2023-08-29 11:47           ` Kalle Valo

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