Re: [PATCH v5] PCI: rcar-gen4: Add missing PM ops

[Marek Vasut <marek.vasut@mailbox.org>]

On 10/16/26 10:55 AM, Manivannan Sadhasivam wrote:
> On 2026-10-04 01:31 +0000, sashiko-bot@kernel.org wrote:
>> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
>> - [High] pcie: deadlocks due to ioremap and request_firmware in NOIRQ PM phase
>> --
>>
>> commit e6c055f1eedf6bd5c13e231da24f0c6a76a24ba2
>> Author: Marek Vasut <marek.vasut+renesas@mailbox.org>
>>
>> PCI: rcar-gen4: Add missing PM ops
>>
>> The R-Car Gen4 PCIe controller needs to gracefully suspend and resume its
>> link across system suspend/resume cycles to support power domains shutting
>> down. This patch adds suspend_noirq and resume_noirq PM operations to tear
>> down the link on suspend and restart it on resume.
>>
>>> diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
>>> index 2e7a8d85c0060..fceecbd16355c 100644
>>> --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
>>> +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
>>
>> [ ... ]
>>
>>> @@ -1062,6 +1064,26 @@ static int rcar_gen4_pcie_ltssm_control(struct rcar_gen4_pcie *rcar, bool enable
>>>   	return 0;
>>>   }
>>>   
>>> +static int rcar_gen4_pcie_suspend_noirq(struct device *dev)
>>> +{
>>> +	struct rcar_gen4_pcie *rcar = dev_get_drvdata(dev);
>>> +
>>> +	if (rcar->drvdata->mode != DW_PCIE_RC_TYPE)
>>> +		return 0;
>>> +
>>> +	return dw_pcie_suspend_noirq(&rcar->dw);
>>                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>
>> [Severity: High]
>> Does this code trigger a deadlock or kernel panic during the NOIRQ PM phase?
>>
>> Setting pp->use_atu_msg to true causes dw_pcie_suspend_noirq() to eventually
>> call ioremap():
>>
>> dw_pcie_suspend_noirq()
>>    dw_pcie_pme_turn_off()
>>      ioremap()
>>
>> Since this runs during the suspend_noirq phase with local interrupts disabled
>> and the system frozen, ioremap() allocates memory with GFP_KERNEL and may
>> sleep, which is strictly prohibited in NOIRQ context.
>>
> 
> What? Local CPU interrupts won't be disbled in the noirq phase, only the device
> interrupts will be. So this concern is utterly baseless.
Do you think we could get this patch into 7.4 since this is a bugfix ?

Thank you !