linux-kernel - Re: [PATCH] HID: intel-ish-hid: Replace PCI_DEV_FLAGS_NO_D3 with pci_save

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Message-Id: <68C336BB-C2E1-4DE4-8137-18F7FBEF140C@canonical.com>
Date:   Fri, 12 Jun 2020 19:43:11 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc:     "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Jiri Kosina <jikos@...nel.org>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Zhang Lixu <lixu.zhang@...el.com>, Even Xu <even.xu@...el.com>,
        Alexios Zavras <alexios.zavras@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Song Hongyan <hongyan.song@...el.com>,
        "open list:INTEL INTEGRATED SENSOR HUB DRIVER" 
        <linux-input@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] HID: intel-ish-hid: Replace PCI_DEV_FLAGS_NO_D3 with
 pci_save_state



> On May 21, 2020, at 12:43, Kai-Heng Feng <kai.heng.feng@...onical.com> wrote:
> 
> Hi Srinivas,
> 
>> On May 9, 2020, at 01:45, Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com> wrote:
>> 
>> On Tue, 2020-05-05 at 21:17 +0800, Kai-Heng Feng wrote:
>>> PCI_DEV_FLAGS_NO_D3 should not be used outside of PCI core.
>>> 
>>> Instead, we can use pci_save_state() to hint PCI core that the device
>>> should stay at D0 during suspend.
>> 
>> Your changes are doing more than just changing the flag. Can you
>> explain more about the other changes?
> 
> By using pci_save_state(), in addition to keep itself stay at D0, the parent bridge will also stay at D0.
> So it's a better approach to achieve the same thing.
> 
>> Also make sure that you test on both platforms which has regular S3 and
>> S0ix (modern standby system).
> 
> Actually I don't have any physical hardware to test the patch, I found the issue when I search for D3 quirks through the source code.
> 
> Can you guys do a quick smoketest for this patch?

Tested this patch on an S2idle system with intel-ish (Latitude 9510) and it works fine.
Please consider merging this patch, thanks!

Kai-Heng

> 
> Kai-Heng
> 
>> 
>> Thanks,
>> Srinivas
>> 
>> 
>>> 
>>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
>>> ---
>>> drivers/hid/intel-ish-hid/ipc/pci-ish.c | 15 ++++++++++-----
>>> 1 file changed, 10 insertions(+), 5 deletions(-)
>>> 
>>> diff --git a/drivers/hid/intel-ish-hid/ipc/pci-ish.c
>>> b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
>>> index f491d8b4e24c..ab588b9c8d09 100644
>>> --- a/drivers/hid/intel-ish-hid/ipc/pci-ish.c
>>> +++ b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
>>> @@ -106,6 +106,11 @@ static inline bool ish_should_enter_d0i3(struct
>>> pci_dev *pdev)
>>> 	return !pm_suspend_via_firmware() || pdev->device ==
>>> CHV_DEVICE_ID;
>>> }
>>> 
>>> +static inline bool ish_should_leave_d0i3(struct pci_dev *pdev)
>>> +{
>>> +	return !pm_resume_via_firmware() || pdev->device ==
>>> CHV_DEVICE_ID;
>>> +}
>>> +
>>> /**
>>> * ish_probe() - PCI driver probe callback
>>> * @pdev:	pci device
>>> @@ -215,9 +220,7 @@ static void __maybe_unused
>>> ish_resume_handler(struct work_struct *work)
>>> 	struct ishtp_device *dev = pci_get_drvdata(pdev);
>>> 	int ret;
>>> 
>>> -	/* Check the NO_D3 flag to distinguish the resume paths */
>>> -	if (pdev->dev_flags & PCI_DEV_FLAGS_NO_D3) {
>>> -		pdev->dev_flags &= ~PCI_DEV_FLAGS_NO_D3;
>>> +	if (ish_should_leave_d0i3(pdev) && !dev->suspend_flag) {
>>> 		disable_irq_wake(pdev->irq);
>>> 
>>> 		ishtp_send_resume(dev);
>>> @@ -281,8 +284,10 @@ static int __maybe_unused ish_suspend(struct
>>> device *device)
>>> 			 */
>>> 			ish_disable_dma(dev);
>>> 		} else {
>>> -			/* Set the NO_D3 flag, the ISH would enter D0i3
>>> */
>>> -			pdev->dev_flags |= PCI_DEV_FLAGS_NO_D3;
>>> +			/* Save state so PCI core will keep the device
>>> at D0,
>>> +			 * the ISH would enter D0i3
>>> +			 */
>>> +			pci_save_state(pdev);
>>> 
>> Did you test on some C
>> 
>> 
>>> 			enable_irq_wake(pdev->irq);
>>> 		}
>