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Message-ID: <2b0ac3c4-74e3-47f1-6aa7-72f2a4176824@quicinc.com>
Date:   Fri, 25 Nov 2022 09:59:33 +0530
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Subject: Re: [PATCH v3 0/3] Enable low power mode when WLAN is not active
To:     Kalle Valo <kvalo@kernel.org>
CC:     <ath11k@lists.infradead.org>, <linux-wireless@vger.kernel.org>
References: <20221121110359.4652-1-quic_mpubbise@quicinc.com>
 <87bkoz8ica.fsf@kernel.org> <87y1s17j1j.fsf@kernel.org>
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From:   Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
In-Reply-To: <87y1s17j1j.fsf@kernel.org>
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On 11/23/2022 9:35 PM, Kalle Valo wrote:
> Kalle Valo <kvalo@kernel.org> writes:
> 
>> Manikanta Pubbisetty <quic_mpubbise@quicinc.com> writes:
>>
>>> Currently, WLAN chip is powered once during driver probe and is kept
>>> ON (powered) always even when WLAN is not active; keeping the chip
>>> powered ON all the time will consume extra power which is not
>>> desirable for battery operated devices. Same is the case with non-WoW
>>> suspend, chip will not be put into low power mode when the system is
>>> suspended resulting in higher battery drain.
>>>
>>> Send QMI MODE OFF command to firmware during WiFi OFF to put device
>>> into low power mode.
>>>
>>> Tested-on: WCN6750 hw1.0 AHB WLAN.MSL.1.0.1-00887-QCAMSLSWPLZ-1
>>> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.16
>>>
>>> Manikanta Pubbisetty (3):
>>>    ath11k: Fix double free issue during SRNG deinit
>>>    ath11k: Move hardware initialization logic to start()
>>>    ath11k: Enable low power mode when WLAN is not active
>>> ---
>>> V3:
>>>   - Removed patch "ath11k: Fix failed to parse regulatory event print" as it is not needed anymore
>>>   - Fixed a potential deadlock scenario reported by lockdep around ab->core_lock with V2 changes
>>>   - Fixed other minor issues that were found during code review
>>>   - Spelling corrections in the commit messages
>>
>> I still see a crash, immediately after the first rmmod:
>>
>> Nov 22 11:05:47 nuc2  [  139.378719] rmmod ath11k_pci
>> Nov 22 11:05:48 nuc2 [ 139.892395] general protection fault, probably
>> for non-canonical address 0xdffffc000000003e: 0000 [#1] PREEMPT SMP
>> DEBUG_PAGEALLOC KASAN
>> Nov 22 11:05:48 nuc2 [ 139.892453] KASAN: null-ptr-deref in range
>> [0x00000000000001f0-0x00000000000001f7]
>>
>> Really odd that you don't see it. Unfortunately not able to debug this
>> further right now.
>>
>> This is with:
>>
>> wcn6855 hw2.0 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.9
> 
> A bit more information how I see the crash. So first I have all modules
> loaded:
> 
> $ lsmod
> Module                  Size  Used by
> ath11k_pci             57344  0
> ath11k               2015232  1 ath11k_pci
> mac80211             3284992  1 ath11k
> libarc4                16384  1 mac80211
> cfg80211             2494464  2 ath11k,mac80211
> qmi_helpers            57344  1 ath11k
> qrtr_mhi               20480  0
> mhi                   217088  2 ath11k_pci,qrtr_mhi
> qrtr                   98304  5 qrtr_mhi
> nvme                  122880  3
> nvme_core             299008  5 nvme
> $
> 
> Then I just remove ath11k_pci module and boom:
> 
> $ sudo rmmod ath11k_pci
> 
> [  153.658409] general protection fault, probably for non-canonical address 0xdffffc000000003e: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN
> 
> This happens every time, there doesn't seem to be any randomness on the
> behaviour.
> 

Thanks for the help Kalle, this is exactly what I was doing in my tests. 
Unfortunately, I'm not able to reproduce the problem. I have also tried 
with the exact firmware that you have pointed out. Let me see if I'm 
missing anything.

Thanks,
Manikanta