On Wed, 07 Aug 2024, Imre Deak <imre.deak@xxxxxxxxx> wrote: > On Wed, Aug 07, 2024 at 12:15:33PM +0300, Murthy, Arun R wrote: >> >> > -----Original Message----- >> > From: Deak, Imre <imre.deak@xxxxxxxxx> >> > Sent: Tuesday, August 6, 2024 10:11 PM >> > To: Murthy, Arun R <arun.r.murthy@xxxxxxxxx> >> > Cc: intel-xe@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx >> > Subject: Re: [PATCH] drm/xe/pm: Change HPD to polling on runtime suspend >> > >> > On Tue, Aug 06, 2024 at 02:25:13PM +0530, Arun R Murthy wrote: >> > > HPD is interrupt based and on runtime suspend change it to polling as >> > > HPD is not a wakeup event. A worker thread is scheduled for doing this >> > > polling and it keeps polling for HPD live status on an internval of 10s. >> > > On runtime resume disable polling and fallback to interrupt mechanism. >> > > >> > > Signed-off-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx> >> > > --- >> > > drivers/gpu/drm/xe/xe_pm.c | 6 ++++++ >> > > 1 file changed, 6 insertions(+) >> > > >> > > diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c >> > > index 9f3c14fd9f33..d952b06ebfb4 100644 >> > > --- a/drivers/gpu/drm/xe/xe_pm.c >> > > +++ b/drivers/gpu/drm/xe/xe_pm.c >> > > @@ -22,6 +22,7 @@ >> > > #include "xe_pcode.h" >> > > #include "xe_trace.h" >> > > #include "xe_wa.h" >> > > +#include "intel_hotplug.h" >> > > >> > > /** >> > > * DOC: Xe Power Management >> > > @@ -378,6 +379,8 @@ int xe_pm_runtime_suspend(struct xe_device *xe) >> > > if (err) >> > > goto out; >> > > } >> > > + /* Enable hpd polling on runtime suspend */ >> > > + intel_hpd_poll_enable(xe); >> > > >> > > xe_irq_suspend(xe); >> > > >> > > @@ -427,6 +430,9 @@ int xe_pm_runtime_resume(struct xe_device *xe) >> > > >> > > xe_irq_resume(xe); >> > > >> > > + /* Disable hpd polling on runtime resume */ >> > > + intel_hpd_poll_disable(xe); >> > >> > This should be handled in xe_display_pm_resume() (likewise enabling polling in >> > xe_display_pm_suspend()), in fact it's already called there. >> >> In xe_display_pm_suspend we have drm_kms_helper_poll_disable and it disables >> output polling. > > What I meant is that intel_hpd_poll_disable() is already called in > xe_display_pm_resume(), which you would call now twice during runtime > resume if d3cold is allowed. > > drm_kms_helper_poll_disable() in xe_display_pm_suspend() should be > called only during system suspend, which is another thing to fix there. > >> Moreover we don't have the functions defined for enable/disable_hpd >> defined in connector_ops which is referenced by >> drm_kms_helper_poll_enable/disable. >> >> What we need is on runtime_suspend the poll work should be >> enabled so that hotplug can be detected and can come out of runtime_suspend. >> The same poll work is not required on system suspend. > > All the display related suspend/resume handling is done already in > xe_display_pm_suspend()/resume() or in xe_display.c in general, both for > runtime and system suspend/resume. The reason for that is to keep the > display specific parts separate from the generic/higher-level device > suspend/resume handling in xe_pm.c. New display specific things added > should keep this separation. I'll keep repeating here too: We should aim to move all of this under i915/display, and not duplicate it in i915 and xe specific code. BR, Jani. > >> > Also this is missing the xe->info.enable_display check and polling shouldn't be >> > enabled when system (vs. runtime) suspending. >> Probably HAS_DISPLAY can be added before calling this intel_hpd_poll_enable. >> >> Thanks and Regards, >> Arun R Murthy >> -------------------- >> > >> > Not sure why the display is suspended/resumed only if d3cold is allowed, for >> > many of the display s/r steps at least it doesn't make sense to me. >> > For now moving the d3cold check within >> > xe_display_pm_suspend()/resume() and enabling/disabling polling regardless of >> > that flag would be the simplest imo. >> > >> > > + >> > > for_each_gt(gt, xe, id) >> > > xe_gt_resume(gt); >> > > >> > > -- >> > > 2.25.1 >> > > -- Jani Nikula, Intel
