Re: [PATCH] ACPI / LPSS: Don't skip late system PM ops for hibernate on BYT/CHT

[Rafael J. Wysocki]

On Thursday, April 25, 2019 6:38:34 PM CEST Robert R. Howell wrote:
> On 4/24/19 1:20 AM, Rafael J. Wysocki wrote:
> 
> > On Tue, Apr 23, 2019 at 10:03 PM Robert R. Howell <RHowell@xxxxxxxx> wrote:
> >>
> >> On 4/23/19 2:07 AM, Rafael J. Wysocki wrote:
> >>>
> >>> On Sat, Apr 20, 2019 at 12:44 AM Robert R. Howell <RHowell@xxxxxxxx> wrote:
> >>>>
> >>>> On 4/18/19 5:42 AM, Hans de Goede wrote:
> >>>>
> >>>>>> On 4/8/19 2:16 AM, Hans de Goede wrote:>
> >>>>>>>
> >>>>>>> Hmm, interesting so you have hibernation working on a T100TA
> >>>>>>> (with 5.0 + 02e45646d53b reverted), right ?
> >>>>>>>
> >>>>
> >>>>
> >>>> I've managed to find a way around the i2c_designware timeout issues
> >>>> on the T100TA's.  The key is to NOT set DPM_FLAG_SMART_SUSPEND,
> >>>> which was added in the 02e45646d53b commit.
> >>>>
> >>>> To test that I've started with a 5.1-rc5 kernel, applied your recent patch
> >>>> to acpi_lpss.c, then apply the following patch of mine, removing
> >>>> DPM_FLAG_SMART_SUSPEND.  (For the T100 hardware I need to apply some
> >>>> other patches as well but those are not related to the i2c-designware or
> >>>> acpi issues addressed here.)
> >>>>
> >>>> On a resume from hibernation I still see one error:
> >>>>   "i2c_designware 80860F41:00: Error i2c_dw_xfer called while suspended"
> >>>> but I no longer get the i2c_designware timeouts, and audio does now work
> >>>> after the resume.
> >>>>
> >>>> Removing DPM_FLAG_SMART_SUSPEND may not be what you want for other
> >>>> hardware, but perhaps this will give you a clue as to what is going
> >>>> wrong with hibernate/resume on the T100TA's.
> >>>
> >>> What if you drop DPM_FLAG_LEAVE_SUSPENDED alone instead?
> >>>
> >>
> >> I did try dropping just DPM_FLAG_LEAVE_SUSPENDED, dropping just
> >> DPM_FLAG_SMART_SUSPEND, and dropping both flags.  When I just drop
> >> DPM_FLAG_LEAVE_SUSPENDED I still get the i2c_designware timeouts
> >> after the resume.  If I drop just DPM_FLAG_SMART_SUSPEND or drop both,
> >> then the timeouts go away.
> > 
> > OK, thanks!
> > 
> > Is non-hibernation system suspend affected too?
> 
> I just ran some tests on a T100TA, using the 5.1-rc5 code with Hans' patch applied 
> but without any changes to i2c-designware-platdrv.c, so the 
> DPM_FLAG_SMART_PREPARE, DPM_FLAG_SMART_SUSPEND, and DPM_FLAG_LEAVE_SUSPENDED flags 
> are all set.  
> 
> Suspend does work OK, and after resume I do NOT get any of the crippling 
> i2c_designware timeout errors which cause sound to fail after hibernate.  I DO see one 
>   "i2c_designware 80860F41:00: Error i2c_dw_xfer call while suspended"
> error on resume, just as I do on hibernate.  I've attached a portion of dmesg below.
> The "asus_wmi:  Unknown key 79 pressed" error is a glitch which occurs 
> intermittently on these machines, but doesn't seem related to the other issues.  
> I had one test run when it was absent but the rest of the messages were the 
> same -- but then kept getting that unknown key error on all my later tries.
> 
> I did notice the "2sidle" in the following rather than "shallow" or "deep".  A
> cat of /sys/power/state shows "freeze mem disk" but a
> cat of /sys/power/mem_sleep" shows only "[s2idle] so it looks like shallow and deep 
> are not enabled for this system.  I did check the input power (or really current) 
> as it went into suspend and the micro-usb power input drops from about 
> 0.5 amps to 0.05 amps.  But clearly a lot of devices are still active, as movement 
> of a bluetooth mouse (the MX Anywhere 2) will wake it from suspend.  That presumably is 
> why suspend doesn't trigger the same i2c_designware problems as hibernate.
> 
> Let me know if I can do any other tests.

Can you please check if the appended patch makes the hibernate issue go away for you, without any other changes?

---
 drivers/pci/pci-driver.c |   36 ++++++++++--------------------------
 1 file changed, 10 insertions(+), 26 deletions(-)

Index: linux-pm/drivers/pci/pci-driver.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-driver.c
+++ linux-pm/drivers/pci/pci-driver.c
@@ -957,15 +957,14 @@ static int pci_pm_freeze(struct device *
 	}
 
 	/*
-	 * This used to be done in pci_pm_prepare() for all devices and some
-	 * drivers may depend on it, so do it here.  Ideally, runtime-suspended
-	 * devices should not be touched during freeze/thaw transitions,
-	 * however.
+	 * Resume all runtime-suspended devices before creating a snapshot
+	 * image of system memory, because the restore kernel generally cannot
+	 * be expected to always handle them consistently and pci_pm_restore()
+	 * always leaves them as "active", so ensure that the state saved in the
+	 * image will always be consistent with that.
 	 */
-	if (!dev_pm_smart_suspend_and_suspended(dev)) {
-		pm_runtime_resume(dev);
-		pci_dev->state_saved = false;
-	}
+	pm_runtime_resume(dev);
+	pci_dev->state_saved = false;
 
 	if (pm->freeze) {
 		int error;
@@ -992,9 +991,6 @@ static int pci_pm_freeze_noirq(struct de
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	struct device_driver *drv = dev->driver;
 
-	if (dev_pm_smart_suspend_and_suspended(dev))
-		return 0;
-
 	if (pci_has_legacy_pm_support(pci_dev))
 		return pci_legacy_suspend_late(dev, PMSG_FREEZE);
 
@@ -1024,16 +1020,6 @@ static int pci_pm_thaw_noirq(struct devi
 	struct device_driver *drv = dev->driver;
 	int error = 0;
 
-	/*
-	 * If the device is in runtime suspend, the code below may not work
-	 * correctly with it, so skip that code and make the PM core skip all of
-	 * the subsequent "thaw" callbacks for the device.
-	 */
-	if (dev_pm_smart_suspend_and_suspended(dev)) {
-		dev_pm_skip_next_resume_phases(dev);
-		return 0;
-	}
-
 	if (pcibios_pm_ops.thaw_noirq) {
 		error = pcibios_pm_ops.thaw_noirq(dev);
 		if (error)
@@ -1093,8 +1079,10 @@ static int pci_pm_poweroff(struct device
 
 	/* The reason to do that is the same as in pci_pm_suspend(). */
 	if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
-	    !pci_dev_keep_suspended(pci_dev))
+	    !pci_dev_keep_suspended(pci_dev)) {
 		pm_runtime_resume(dev);
+		pci_dev->state_saved = false;
+	}
 
 	pci_dev->state_saved = false;
 	if (pm->poweroff) {
@@ -1168,10 +1156,6 @@ static int pci_pm_restore_noirq(struct d
 	struct device_driver *drv = dev->driver;
 	int error = 0;
 
-	/* This is analogous to the pci_pm_resume_noirq() case. */
-	if (dev_pm_smart_suspend_and_suspended(dev))
-		pm_runtime_set_active(dev);
-
 	if (pcibios_pm_ops.restore_noirq) {
 		error = pcibios_pm_ops.restore_noirq(dev);
 		if (error)