Re: [PATCH 2/3] PCI: dwc: Use common D3cold eligibility helper in suspend path

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

On 1/28/2026 7:58 PM, Bjorn Andersson wrote:
> On Wed, Jan 28, 2026 at 05:10:42PM +0530, Krishna Chaitanya Chundru wrote:
>> Previously, the driver skipped putting the link into L2/device state in
>> D3cold whenever L1 ASPM was enabled, since some devices (e.g. NVMe) expect
>> low resume latency and may not tolerate deeper power states. However, such
>> devices typically remain in D0 and are already covered by the new helper's
>> requirement that all endpoints be in D3hot before the host bridge may
>> enter D3cold.
>>
>> So, replace the local L1/L1SS-based check in dw_pcie_suspend_noirq() with
>> the shared pci_host_common_can_enter_d3cold() helper to decide whether the
>> DesignWare host bridge can safely transition to D3cold.
>>
>> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
>> ---
>>   drivers/pci/controller/dwc/pcie-designware-host.c | 7 +------
>>   drivers/pci/controller/dwc/pcie-designware.h      | 1 +
>>   2 files changed, 2 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
>> index 372207c33a857b4c98572bb1e9b61fa0080bc871..2c8056761addf7febc1b0e06ddf8ba4dd4ad1684 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
>> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
>> @@ -1157,15 +1157,10 @@ static int dw_pcie_pme_turn_off(struct dw_pcie *pci)
>>   
>>   int dw_pcie_suspend_noirq(struct dw_pcie *pci)
>>   {
>> -	u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
>>   	u32 val;
>>   	int ret;
>>   
>> -	/*
>> -	 * 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)
>> +	if (!pci_host_common_can_enter_d3cold(pci->pp.bridge))
>>   		return 0;
>>   
>>   	if (pci->pp.ops->pme_turn_off) {
>> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
>> index 31685951a080456b8834aab2bf79a36c78f46639..18d8f7d5d23088b2fa177e84a21d900c98850fcd 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware.h
>> +++ b/drivers/pci/controller/dwc/pcie-designware.h
>> @@ -26,6 +26,7 @@
>>   #include <linux/pci-epc.h>
>>   #include <linux/pci-epf.h>
>>   
>> +#include "../pci-host-common.h"
> Why doesn't this include go in the c file? I don't see that all c files
Ack, will do this in v2.

- Krishna Chaitanya.
> including pcie-designware.h now needs this.
>
> Regards,
> Bjorn
>
>>   #include "../../pci.h"
>>   
>>   /* DWC PCIe IP-core versions (native support since v4.70a) */
>>
>> -- 
>> 2.34.1
>>
>>