Re: [PATCH v2 1/2] PCI/ASPM: Override the ASPM and Clock PM states set by BIOS for devicetree platforms

[Jon Hunter <jonathanh@nvidia.com>]

On 11/05/2026 06:18, Manivannan Sadhasivam wrote:
> On Thu, May 07, 2026 at 11:25:23AM +0100, Jon Hunter wrote:
>> Hi Bjorn, Mani,
>>
>> On 22/01/2026 15:29, Bjorn Helgaas wrote:
>>> [+cc NVMe folks]
>>>
>>> On Thu, Jan 22, 2026 at 12:12:42PM +0000, Jon Hunter wrote:
>>>> ...
>>>
>>>> Since this commit was added in Linux v6.18, I have been observing a suspend
>>>> test failures on some of our boards. The suspend test suspends the devices
>>>> for 20 secs and before this change the board would resume in about ~27 secs
>>>> (including the 20 sec sleep). After this change the board would take over 80
>>>> secs to resume and this triggered a failure.
>>>>
>>>> Looking at the logs, I can see it is the NVMe device on the board that is
>>>> having an issue, and I see the reset failing ...
>>>>
>>>>    [  945.754939] r8169 0007:01:00.0 enP7p1s0: Link is Up - 1Gbps/Full -
>>>>     flow control rx/tx
>>>>    [ 1002.467432] nvme nvme0: I/O tag 12 (400c) opcode 0x9 (Admin Cmd) QID
>>>>     0 timeout, reset controller
>>>>    [ 1002.493713] nvme nvme0: 12/0/0 default/read/poll queues
>>>>    [ 1003.050448] nvme nvme0: ctrl state 1 is not RESETTING
>>>>    [ 1003.050481] OOM killer enabled.
>>>>    [ 1003.054035] nvme nvme0: Disabling device after reset failure: -19
>>>>
>>>>   From the above timestamps the delay is coming from the NVMe. I see this
>>>> issue on several boards with different NVMe devices and I can workaround
>>>> this by disabling ASPM L0/L1 for these devices ...
>>>>
>>>>    DECLARE_PCI_FIXUP_HEADER(0x15b7, 0x5011, quirk_disable_aspm_l0s_l1);
>>>>    DECLARE_PCI_FIXUP_HEADER(0x15b7, 0x5036, quirk_disable_aspm_l0s_l1);
>>>>    DECLARE_PCI_FIXUP_HEADER(0x1b4b, 0x1322, quirk_disable_aspm_l0s_l1);
>>>>    DECLARE_PCI_FIXUP_HEADER(0xc0a9, 0x540a, quirk_disable_aspm_l0s_l1);
>>>>
>>>> I am curious if you have seen any similar issues?
>>>>
>>>> Other PCIe devices seem to be OK (like the realtek r8169) but just
>>>> the NVMe is having issues. So I am trying to figure out the best way
>>>> to resolve this?
>>>
>>> For context, "this commit" refers to f3ac2ff14834, modified by
>>> df5192d9bb0e:
>>>
>>>     f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devicetree platforms")
>>>     df5192d9bb0e ("PCI/ASPM: Enable only L0s and L1 for devicetree platforms")
>>>
>>> The fact that this suspend issue only affects NVMe reminds me of the
>>> code in dw_pcie_suspend_noirq() [1] that bails out early if L1 is
>>> enabled because of some NVMe expectation:
>>>
>>>     dw_pcie_suspend_noirq()
>>>     {
>>>       ...
>>>       /*
>>>        * If L1SS is supported, then do not put the link into L2 as some
>>>        * devices such as NVMe expect low resume latency.
>>>        */
>>>       if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1)
>>>         return 0;
>>>       ...
>>>
>>> That suggests there's some NVMe/ASPM interaction that the PCI core
>>> doesn't understand yet.
>>>
>>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/controller/dwc/pcie-designware-host.c?id=v6.18#n1146
>>
>>
>> I want to revisit this issue. From my perspective low-power suspend has now
>> been broken on some of our Tegra platforms (that have NVMe devices) since
>> v6.19 and so far this is no resolution to this issue. The patch that was
>> proposed to fix this [0] has been rejected by qualcomm and although this
>> does workaround the issue, my confidence that this is the right fix is now
>> low.
>>
> 
> The referenced patch is now merged into arm-soc for v7.2:
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=7602c0ec0bbfd3985d49f4f0cad281c1414008c9
> 
> I hope this takes care of the issue you are dealing with.

Well yes this patch does fix issues for us. However, I am still a bit 
confused about this whole thing given that this patch does not work for 
all qualcomm platforms. Anyway, I guess we have not seen any other 
issues so far with the above and so may be we can consider this closed 
for now.

Thanks
Jon

-- 
nvpublic