https://bugzilla.kernel.org/show_bug.cgi?id=212951
--- Comment #13 from Chris Chiu (chris.c...@canonical.com) --- I got this problem fixed with the following hacky code and I think it should be a finding that could help. ``` --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -1399,6 +1399,15 @@ static int i915_pm_poweroff_late(struct device *kdev) return i915_drm_suspend_late(&i915->drm, true); } +static int i915_pm_resume_noirq(struct device *kdev) +{ + struct drm_i915_private *i915 = kdev_to_i915(kdev); + + if (!IS_VALLEYVIEW(i915) && !IS_CHERRYVIEW(i915)) + intel_hpd_init(i915); + return 0; +} + static int i915_pm_resume_early(struct device *kdev) { struct drm_i915_private *i915 = kdev_to_i915(kdev); @@ -1626,6 +1635,7 @@ const struct dev_pm_ops i915_pm_ops = { .prepare = i915_pm_prepare, .suspend = i915_pm_suspend, .suspend_late = i915_pm_suspend_late, + .resume_noirq = i915_pm_resume_noirq, .resume_early = i915_pm_resume_early, .resume = i915_pm_resume, ``` Because this APCI method IPCS lockup only happens when we remove the dock with external display connected(or the USB-C dongle with external display connected) when suspended and then exit s2idle. It should be related to either graphic drivers or hpd events handling. I did lots of experiments and found if the \_SB.PC00.PEG1.PG01._ON exeutes after i915_pm_resume_early, the IPCS will not be locked by the IBSY and IERR. Since the \_SB.PC00.PEG1.PG01._ON is invoked by pci_power_up() in pci_pm_resume_noirq and it's in the context of dpm_resume_noirq(). The i915_pm_resume_early is in dpm_resume_early() context and that's why the Sleep(One) in the IPCS lasts for >30 seconds but i915 still has no chance to early resume to free the IPCS lock. I assume that it's due to the unplug action is not handled properly during resume, so I add the .resume_noirq() in i915 driver to let the hpd have chance to do something during in the same dpm_resume_noirq context. It seems to work fine and pci 0000:01:00.0 (PEG1) can transition to D0 w/o problem. However, it's a dirty hack because I'll hit the kernel WARN in hpd_init(). Please refer to the attached hpd_init_dmesg.log. Can anyone from Intel help on this? I'll be glad to collect logs or test any PATCH. Thanks -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug. _______________________________________________ acpi-bugzilla mailing list acpi-bugzilla@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla