drm/xe: Move d3cold_allowed decision all together.

And let's use the VRAM threshold to keep d3cold temporarily disabled.

With this we have the ability to run D3Cold experiments just by
touching the vram_d3cold_threshold sysfs entry.

Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_pci.c

@@ -806,21 +806,8 @@ static int xe_pci_runtime_idle(struct device *dev)
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct xe_device *xe = pdev_to_xe_device(pdev);
 
-	if (!xe->d3cold.capable) {
-		xe->d3cold.allowed = false;
-	} else {
 	xe_pm_d3cold_allowed_toggle(xe);
 
-		/*
-		 * TODO: d3cold should be allowed (true) if
-		 * (IS_DGFX(xe) && !xe_device_mem_access_ongoing(xe))
-		 * but maybe include some other conditions. So, before
-		 * we can re-enable the D3cold, we need to:
-		 * 1. rewrite the VRAM save / restore to avoid buffer object locks
-		 */
-		xe->d3cold.allowed = false;
-	}
-
 	return 0;
 }
 #endif

drivers/gpu/drm/xe/xe_pm.c

@@ -342,6 +342,11 @@ void xe_pm_d3cold_allowed_toggle(struct xe_device *xe)
 	u64 vram_used;
 	int i;
 
+	if (!xe->d3cold.capable) {
+		xe->d3cold.allowed = false;
+		return;
+	}
+
 	for (i = XE_PL_VRAM0; i <= XE_PL_VRAM1; ++i) {
 		man = ttm_manager_type(&xe->ttm, i);
 		if (man) {

drivers/gpu/drm/xe/xe_pm.h

@@ -8,7 +8,12 @@
 
 #include <linux/pm_runtime.h>
 
-#define DEFAULT_VRAM_THRESHOLD 300 /* in MB */
+/*
+ * TODO: Threshold = 0 will block D3Cold.
+ *       Before we can move this to a higher value (like 300), we need to:
+ *           1. rewrite the VRAM save / restore to avoid buffer object locks
+ */
+#define DEFAULT_VRAM_THRESHOLD 0 /* in MB */
 
 struct xe_device;