* [PATCH] PCI: qcom: Ignore -ENODEV after Root Port reset
@ 2026-09-16 12:37 Konrad Dybcio
2026-09-16 13:37 ` Krishna Chaitanya Chundru
2026-09-16 15:53 ` Niklas Cassel
0 siblings, 2 replies; 5+ messages in thread
From: Konrad Dybcio @ 2026-09-16 12:37 UTC (permalink / raw)
To: Manivannan Sadhasivam, Lorenzo Pieralisi,
Krzysztof Wilczyński, Rob Herring, Bjorn Helgaas,
Krishna Chaitanya Chundru
Cc: linux-arm-msm, linux-pci, linux-kernel, Manivannan Sadhasivam,
Konrad Dybcio
Root Port recovery may race with a device hot-unplug. In that case,
dw_pcie_wait_for_link() returns -ENODEV because no device is detected
after the controller has been successfully reset.
This is a valid outcome and should not cause Root Port recovery to
fail. Ignore -ENODEV while continuing to propagate other link-training
errors.
Assisted-by: LLM
Fixes: 4d88cb82a6d9 ("PCI: qcom: Implement .reset_root_port() and use for link down")
Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
drivers/pci/controller/dwc/pcie-qcom.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index ee63a6ec99de4d07c16b8d6cb68df0d92f822cd8..3d3be9bf798b7c247d69969d6570385b8648123f 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1880,6 +1880,9 @@ static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
qcom_pcie_start_link(pci);
ret = dw_pcie_wait_for_link(pci);
+ /* This linkdown might have been a hot-unplug */
+ if (ret == -ENODEV)
+ ret = 0;
if (ret)
return ret;
---
base-commit: e6e35979777d646fe3c7c94dca7dd32fb25d45f4
change-id: 20260916-topic-pcie_portrec_enodev-cc576ea927f9
Best regards,
--
Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] PCI: qcom: Ignore -ENODEV after Root Port reset
2026-09-16 12:37 [PATCH] PCI: qcom: Ignore -ENODEV after Root Port reset Konrad Dybcio
@ 2026-09-16 13:37 ` Krishna Chaitanya Chundru
2026-09-16 15:53 ` Niklas Cassel
1 sibling, 0 replies; 5+ messages in thread
From: Krishna Chaitanya Chundru @ 2026-09-16 13:37 UTC (permalink / raw)
To: Konrad Dybcio, Manivannan Sadhasivam, Lorenzo Pieralisi,
Krzysztof Wilczyński, Rob Herring, Bjorn Helgaas
Cc: linux-arm-msm, linux-pci, linux-kernel, Manivannan Sadhasivam
On 9/16/2026 6:07 PM, Konrad Dybcio wrote:
> Root Port recovery may race with a device hot-unplug. In that case,
> dw_pcie_wait_for_link() returns -ENODEV because no device is detected
> after the controller has been successfully reset.
>
> This is a valid outcome and should not cause Root Port recovery to
> fail. Ignore -ENODEV while continuing to propagate other link-training
> errors.
>
> Assisted-by: LLM
> Fixes: 4d88cb82a6d9 ("PCI: qcom: Implement .reset_root_port() and use for link down")
> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
- Krishna Chaitanya.
> ---
> drivers/pci/controller/dwc/pcie-qcom.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index ee63a6ec99de4d07c16b8d6cb68df0d92f822cd8..3d3be9bf798b7c247d69969d6570385b8648123f 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1880,6 +1880,9 @@ static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
> qcom_pcie_start_link(pci);
>
> ret = dw_pcie_wait_for_link(pci);
> + /* This linkdown might have been a hot-unplug */
> + if (ret == -ENODEV)
> + ret = 0;
> if (ret)
> return ret;
>
>
> ---
> base-commit: e6e35979777d646fe3c7c94dca7dd32fb25d45f4
> change-id: 20260916-topic-pcie_portrec_enodev-cc576ea927f9
>
> Best regards,
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] PCI: qcom: Ignore -ENODEV after Root Port reset
2026-09-16 12:37 [PATCH] PCI: qcom: Ignore -ENODEV after Root Port reset Konrad Dybcio
2026-09-16 13:37 ` Krishna Chaitanya Chundru
@ 2026-09-16 15:53 ` Niklas Cassel
2026-09-16 16:13 ` Konrad Dybcio
1 sibling, 1 reply; 5+ messages in thread
From: Niklas Cassel @ 2026-09-16 15:53 UTC (permalink / raw)
To: Konrad Dybcio
Cc: Manivannan Sadhasivam, Lorenzo Pieralisi,
Krzysztof Wilczyński, Rob Herring, Bjorn Helgaas,
Krishna Chaitanya Chundru, linux-arm-msm, linux-pci,
linux-kernel, Manivannan Sadhasivam
Hello Konrad,
On Wed, Sep 16, 2026 at 02:37:49PM +0200, Konrad Dybcio wrote:
> Root Port recovery may race with a device hot-unplug. In that case,
> dw_pcie_wait_for_link() returns -ENODEV because no device is detected
> after the controller has been successfully reset.
>
> This is a valid outcome and should not cause Root Port recovery to
> fail. Ignore -ENODEV while continuing to propagate other link-training
> errors.
>
> Assisted-by: LLM
> Fixes: 4d88cb82a6d9 ("PCI: qcom: Implement .reset_root_port() and use for link down")
> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> ---
> drivers/pci/controller/dwc/pcie-qcom.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index ee63a6ec99de4d07c16b8d6cb68df0d92f822cd8..3d3be9bf798b7c247d69969d6570385b8648123f 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1880,6 +1880,9 @@ static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
> qcom_pcie_start_link(pci);
>
> ret = dw_pcie_wait_for_link(pci);
> + /* This linkdown might have been a hot-unplug */
> + if (ret == -ENODEV)
> + ret = 0;
> if (ret)
> return ret;
I did not know that pcie-qcom supported hotplug.
Last when I was discussing this with Mani, I'm quite sure that he said that
it doesn't, see:
https://lore.kernel.org/all/20251222064207.3246632-8-cassel@kernel.org/
If that is the case, perhaps the commit message and code comment should be
clarified, so it is more clear what it actually means.
Kind regards,
Niklas
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] PCI: qcom: Ignore -ENODEV after Root Port reset
2026-09-16 15:53 ` Niklas Cassel
@ 2026-09-16 16:13 ` Konrad Dybcio
2026-09-16 16:24 ` Niklas Cassel
0 siblings, 1 reply; 5+ messages in thread
From: Konrad Dybcio @ 2026-09-16 16:13 UTC (permalink / raw)
To: Niklas Cassel
Cc: Manivannan Sadhasivam, Lorenzo Pieralisi,
Krzysztof Wilczyński, Rob Herring, Bjorn Helgaas,
Krishna Chaitanya Chundru, linux-arm-msm, linux-pci,
linux-kernel, Manivannan Sadhasivam
On 9/16/26 5:53 PM, Niklas Cassel wrote:
> Hello Konrad,
>
> On Wed, Sep 16, 2026 at 02:37:49PM +0200, Konrad Dybcio wrote:
>> Root Port recovery may race with a device hot-unplug. In that case,
>> dw_pcie_wait_for_link() returns -ENODEV because no device is detected
>> after the controller has been successfully reset.
>>
>> This is a valid outcome and should not cause Root Port recovery to
>> fail. Ignore -ENODEV while continuing to propagate other link-training
>> errors.
>>
>> Assisted-by: LLM
>> Fixes: 4d88cb82a6d9 ("PCI: qcom: Implement .reset_root_port() and use for link down")
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>> ---
>> drivers/pci/controller/dwc/pcie-qcom.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
>> index ee63a6ec99de4d07c16b8d6cb68df0d92f822cd8..3d3be9bf798b7c247d69969d6570385b8648123f 100644
>> --- a/drivers/pci/controller/dwc/pcie-qcom.c
>> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
>> @@ -1880,6 +1880,9 @@ static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
>> qcom_pcie_start_link(pci);
>>
>> ret = dw_pcie_wait_for_link(pci);
>> + /* This linkdown might have been a hot-unplug */
>> + if (ret == -ENODEV)
>> + ret = 0;
>> if (ret)
>> return ret;
>
>
> I did not know that pcie-qcom supported hotplug.
>
> Last when I was discussing this with Mani, I'm quite sure that he said that
> it doesn't, see:
> https://lore.kernel.org/all/20251222064207.3246632-8-cassel@kernel.org/
I don't know if native ports still don't, but the ones used for USB4
tunneling certainly do
see e.g.:
65ccb2203ef8 ("PCI: qcom: Clear Attention Button Present in Slot Capabilities")
Konrad
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] PCI: qcom: Ignore -ENODEV after Root Port reset
2026-09-16 16:13 ` Konrad Dybcio
@ 2026-09-16 16:24 ` Niklas Cassel
0 siblings, 0 replies; 5+ messages in thread
From: Niklas Cassel @ 2026-09-16 16:24 UTC (permalink / raw)
To: Konrad Dybcio
Cc: Manivannan Sadhasivam, Lorenzo Pieralisi,
Krzysztof Wilczyński, Rob Herring, Bjorn Helgaas,
Krishna Chaitanya Chundru, linux-arm-msm, linux-pci,
linux-kernel, Manivannan Sadhasivam
On Wed, Sep 16, 2026 at 06:13:29PM +0200, Konrad Dybcio wrote:
> On 9/16/26 5:53 PM, Niklas Cassel wrote:
> > Hello Konrad,
> >
> > On Wed, Sep 16, 2026 at 02:37:49PM +0200, Konrad Dybcio wrote:
> >> Root Port recovery may race with a device hot-unplug. In that case,
> >> dw_pcie_wait_for_link() returns -ENODEV because no device is detected
> >> after the controller has been successfully reset.
> >>
> >> This is a valid outcome and should not cause Root Port recovery to
> >> fail. Ignore -ENODEV while continuing to propagate other link-training
> >> errors.
> >>
> >> Assisted-by: LLM
> >> Fixes: 4d88cb82a6d9 ("PCI: qcom: Implement .reset_root_port() and use for link down")
> >> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> >> ---
> >> drivers/pci/controller/dwc/pcie-qcom.c | 3 +++
> >> 1 file changed, 3 insertions(+)
> >>
> >> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> >> index ee63a6ec99de4d07c16b8d6cb68df0d92f822cd8..3d3be9bf798b7c247d69969d6570385b8648123f 100644
> >> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> >> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> >> @@ -1880,6 +1880,9 @@ static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
> >> qcom_pcie_start_link(pci);
> >>
> >> ret = dw_pcie_wait_for_link(pci);
> >> + /* This linkdown might have been a hot-unplug */
> >> + if (ret == -ENODEV)
> >> + ret = 0;
> >> if (ret)
> >> return ret;
> >
> >
> > I did not know that pcie-qcom supported hotplug.
> >
> > Last when I was discussing this with Mani, I'm quite sure that he said that
> > it doesn't, see:
> > https://lore.kernel.org/all/20251222064207.3246632-8-cassel@kernel.org/
>
> I don't know if native ports still don't, but the ones used for USB4
> tunneling certainly do
>
> see e.g.:
> 65ccb2203ef8 ("PCI: qcom: Clear Attention Button Present in Slot Capabilities")
Ok, nice to see :)
Kind regards,
Niklas
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2026-09-16 16:24 UTC | newest]
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2026-09-16 12:37 [PATCH] PCI: qcom: Ignore -ENODEV after Root Port reset Konrad Dybcio
2026-09-16 13:37 ` Krishna Chaitanya Chundru
2026-09-16 15:53 ` Niklas Cassel
2026-09-16 16:13 ` Konrad Dybcio
2026-09-16 16:24 ` Niklas Cassel
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