linux-kernel - Re: [PATCH 4/6] wifi: ath12k: Use pci_{enable/disable}_link_state() APIs to enable/disable ASPM states

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Message-ID: <03806d02-1cfc-4db2-8b63-c1e51f5456e2@oss.qualcomm.com>
Date: Thu, 17 Jul 2025 18:46:12 +0800
From: Baochen Qiang <baochen.qiang@....qualcomm.com>
To: Manivannan Sadhasivam <mani@...nel.org>
Cc: manivannan.sadhasivam@....qualcomm.com,
        Jeff Johnson
 <jjohnson@...nel.org>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kwilczynski@...nel.org>,
        Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
        Nirmal Patel <nirmal.patel@...ux.intel.com>,
        Jonathan Derrick <jonathan.derrick@...ux.dev>,
        linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org,
        ath12k@...ts.infradead.org, ath11k@...ts.infradead.org,
        ath10k@...ts.infradead.org, Bjorn Helgaas <helgaas@...nel.org>,
        ilpo.jarvinen@...ux.intel.com, linux-arm-msm@...r.kernel.org,
        linux-pci@...r.kernel.org,
        Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>,
        Qiang Yu <qiang.yu@....qualcomm.com>
Subject: Re: [PATCH 4/6] wifi: ath12k: Use pci_{enable/disable}_link_state()
 APIs to enable/disable ASPM states



On 7/17/2025 6:31 PM, Manivannan Sadhasivam wrote:
> On Thu, Jul 17, 2025 at 05:24:13PM GMT, Baochen Qiang wrote:
> 
> [...]
> 
>>> @@ -16,6 +16,8 @@
>>>  #include "mhi.h"
>>>  #include "debug.h"
>>>  
>>> +#include "../ath.h"
>>> +
>>>  #define ATH12K_PCI_BAR_NUM		0
>>>  #define ATH12K_PCI_DMA_MASK		36
>>>  
>>> @@ -928,8 +930,7 @@ static void ath12k_pci_aspm_disable(struct ath12k_pci *ab_pci)
>>>  		   u16_get_bits(ab_pci->link_ctl, PCI_EXP_LNKCTL_ASPM_L1));
>>>  
>>>  	/* disable L0s and L1 */
>>> -	pcie_capability_clear_word(ab_pci->pdev, PCI_EXP_LNKCTL,
>>> -				   PCI_EXP_LNKCTL_ASPMC);
>>> +	pci_disable_link_state(ab_pci->pdev, PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
>>
>> Not always, but sometimes seems the 'disable' does not work:
>>
>> [  279.920507] ath12k_pci_power_up 1475: link_ctl 0x43 //before disable
>> [  279.920539] ath12k_pci_power_up 1482: link_ctl 0x43 //after disable
>>
>>
>>>  
>>>  	set_bit(ATH12K_PCI_ASPM_RESTORE, &ab_pci->flags);
>>>  }
>>> @@ -958,10 +959,7 @@ static void ath12k_pci_aspm_restore(struct ath12k_pci *ab_pci)
>>>  {
>>>  	if (ab_pci->ab->hw_params->supports_aspm &&
>>>  	    test_and_clear_bit(ATH12K_PCI_ASPM_RESTORE, &ab_pci->flags))
>>> -		pcie_capability_clear_and_set_word(ab_pci->pdev, PCI_EXP_LNKCTL,
>>> -						   PCI_EXP_LNKCTL_ASPMC,
>>> -						   ab_pci->link_ctl &
>>> -						   PCI_EXP_LNKCTL_ASPMC);
>>> +		pci_enable_link_state(ab_pci->pdev, ath_pci_aspm_state(ab_pci->link_ctl));
>>
>> always, the 'enable' is not working:
>>
>> [  280.561762] ath12k_pci_start 1180: link_ctl 0x43 //before restore
>> [  280.561809] ath12k_pci_start 1185: link_ctl 0x42 //after restore
>>
> 
> Interesting! I applied your diff and I never see this issue so far (across 10+
> reboots):

I was not testing reboot. Here is what I am doing:

step1: rmmod ath12k
step2: force LinkCtrl using setpci (make sure it is 0x43, which seems more likely to see
the issue)

	sudo setpci -s 02:00.0 0x80.B=0x43

step3: insmod ath12k and check linkctrl

> 
> [    3.758239] ath12k_pci_power_up 1475: link_ctl 0x42
> [    3.758315] ath12k_pci_power_up 1480: link_ctl 0x40
> [    4.383900] ath12k_pci_start 1180: link_ctl 0x40
> [    4.384026] ath12k_pci_start 1185: link_ctl 0x42
> 
> Are you sure that you applied all the 6 patches in the series and not just the
> ath patches? Because, the first 3 PCI core patches are required to make the API
> work as intended.

pretty sure all of them:

$ git log --oneline
07387d1bc17f (HEAD -> VALIDATE-pci-enable-link-state-behavior) wifi: ath12k: dump linkctrl reg
dbb3e5a7828b wifi: ath10k: Use pci_{enable/disable}_link_state() APIs to enable/disable
ASPM states
392d7b3486b3 wifi: ath11k: Use pci_{enable/disable}_link_state() APIs to enable/disable
ASPM states
f2b0685c456d wifi: ath12k: Use pci_{enable/disable}_link_state() APIs to enable/disable
ASPM states
b1c8fad998f1 PCI/ASPM: Improve the kernel-doc for pci_disable_link_state*() APIs
b8f5204ba4b0 PCI/ASPM: Transition the device to D0 (if required) inside
pci_enable_link_state_locked() API
186b1bbd4c62 PCI/ASPM: Fix the behavior of pci_enable_link_state*() APIs
5a1ad8faaa16 (tag: ath-202507151704, origin/master, origin/main, origin/HEAD) Add
localversion-wireless-testing-ath


> 
>>
>>>  }
>>>  
>>>  static void ath12k_pci_cancel_workqueue(struct ath12k_base *ab)
>>>
>>
>> In addition, frequently I can see below AER warnings:
>>
>> [  280.383143] aer_ratelimit: 30 callbacks suppressed
>> [  280.383151] pcieport 0000:00:1c.0: AER: Correctable error message received from
>> 0000:00:1c.0
>> [  280.383177] pcieport 0000:00:1c.0: PCIe Bus Error: severity=Correctable, type=Data Link
>> Layer, (Transmitter ID)
>> [  280.383184] pcieport 0000:00:1c.0:   device [8086:7ab8] error status/mask=00001000/00002000
>> [  280.383193] pcieport 0000:00:1c.0:    [12] Timeout
>>
> 
> I don't see any AER errors either.

My WLAN chip is attached via a PCIe-to-M.2 adapter, maybe some hardware issue? However I
never saw them until your changes applied.

> 
> - Mani
>