[PATCHv3] drm/xe/display: Change HPD to polling on runtime suspend

[Arun R Murthy <arun.r.murthy@intel.com>]

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.

v2: move poll_enable() to xe_display(Imre)
v3: removed un-wanted comments (Jani)

Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
---
 drivers/gpu/drm/xe/display/xe_display.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
index 78cccbe28947..426b3f73c104 100644
--- a/drivers/gpu/drm/xe/display/xe_display.c
+++ b/drivers/gpu/drm/xe/display/xe_display.c
@@ -315,6 +315,9 @@ void xe_display_pm_suspend(struct xe_device *xe, bool runtime)
 
 	intel_hpd_cancel_work(xe);
 
+	if (runtime)
+		intel_hpd_poll_enable(xe);
+
 	intel_suspend_encoders(xe);
 
 	intel_opregion_suspend(xe, s2idle ? PCI_D1 : PCI_D3cold);
-- 
2.25.1