> -----Original Message----- > From: Vivi, Rodrigo <rodrigo.vivi@xxxxxxxxx> > Sent: Wednesday, July 20, 2022 7:33 PM > To: Gupta, Anshuman <anshuman.gupta@xxxxxxxxx> > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Summers, Stuart > <stuart.summers@xxxxxxxxx> > Subject: Re: [PATCH] drm/i915/dg1: Disable D3 for gfx's VSP > > On Wed, Jul 20, 2022 at 06:51:37PM +0530, Anshuman Gupta wrote: > > When DG1 gfx pci endpoint's parent upstream bridge (VSP) enters to D3, > > any direct memory read from lmem returns with 0xff. > > DG1 requires i915 driven runtime resume in order to read properly from > > lmem, DG1 is unable to wakeup from local memory reads. > > This may breaks using mmap() with lmem object on DG1 as it relies on > > mercy of i915 driven runtime resume. > > why our disable at root_port not working to block this case? > If the root power is not at D3Cold our power shouldn't be cut and our memory > should be there. This is not d3cold issue, there was no ACPI real_power_state means d3cold was not supported. the issue here is reading from memory is not transitioning the d3 -> d0 on DG1. As far as I understand , reading form mmap memory will not cause i915 kernel wakeup. It will be a device wakeup (D3-> D0) without any i915 runtime resume, If we force dpms_on before accessing mmap region. It can read the valid data from lmem. Thanks, Anshuman Gupta. > > > > > Let's not break using mmap() for lmem object on DG1. > > Using pci_d3cold_disable(i915) accordingly to disable D3 for upstream > > bridge. > > > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6331 > > Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > > Signed-off-by: Anshuman Gupta <anshuman.gupta@xxxxxxxxx> > > --- > > drivers/gpu/drm/i915/intel_runtime_pm.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c > > b/drivers/gpu/drm/i915/intel_runtime_pm.c > > index 6ed5786bcd29..671009fd351a 100644 > > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c > > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c > > @@ -559,6 +559,7 @@ void intel_runtime_pm_enable(struct > intel_runtime_pm *rpm) > > struct drm_i915_private *i915 = container_of(rpm, > > struct drm_i915_private, > > runtime_pm); > > + struct pci_dev *pdev = to_pci_dev(i915->drm.dev); > > struct device *kdev = rpm->kdev; > > > > /* > > @@ -574,6 +575,9 @@ void intel_runtime_pm_enable(struct > intel_runtime_pm *rpm) > > pm_runtime_set_autosuspend_delay(kdev, 10000); /* 10s */ > > pm_runtime_mark_last_busy(kdev); > > > > + if (IS_DG1(i915)) > > + pci_d3cold_disable(pdev); > > + > > /* > > * Take a permanent reference to disable the RPM functionality and > drop > > * it only when unloading the driver. Use the low level get/put > > helpers, @@ -607,12 +611,16 @@ void intel_runtime_pm_disable(struct > intel_runtime_pm *rpm) > > struct drm_i915_private *i915 = container_of(rpm, > > struct drm_i915_private, > > runtime_pm); > > + struct pci_dev *pdev = to_pci_dev(i915->drm.dev); > > struct device *kdev = rpm->kdev; > > > > /* Transfer rpm ownership back to core */ > > drm_WARN(&i915->drm, pm_runtime_get_sync(kdev) < 0, > > "Failed to pass rpm ownership back to core\n"); > > > > + if (IS_DG1(i915)) > > + pci_d3cold_enable(pdev); > > + > > pm_runtime_dont_use_autosuspend(kdev); > > > > if (!rpm->available) > > -- > > 2.26.2 > >
