drm/i915: Disable RPG during live selftest

The Forcewake timeout issue has been observed on Gen 12.0 and above.
To address this, disable Render Power-Gating (RPG) during live self-tests
for these generations. The temporary workaround 'drm/i915/mtl: do not
enable render power-gating on MTL' disables RPG globally, which is
unnecessary since the issues were only seen during self-tests.

v2: take runtime pm wakeref

Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/9413
Fixes: 25e7976 ("drm/i915/mtl: do not enable render power-gating on MTL")
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Signed-off-by: Sk Anirban <sk.anirban@intel.com>
Reviewed-by: Karthik Poosa <karthik.poosa@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250310152821.2931678-1-sk.anirban@intel.com
(cherry picked from commit 0a4ae87706c6d15d14648e428c3a76351f823e48)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/gt/intel_rc6.c

@@ -117,21 +117,10 @@ static void gen11_rc6_enable(struct intel_rc6 *rc6)
 			GEN6_RC_CTL_RC6_ENABLE |
 			GEN6_RC_CTL_EI_MODE(1);
 
-	/*
-	 * BSpec 52698 - Render powergating must be off.
-	 * FIXME BSpec is outdated, disabling powergating for MTL is just
-	 * temporary wa and should be removed after fixing real cause
-	 * of forcewake timeouts.
-	 */
-	if (IS_GFX_GT_IP_RANGE(gt, IP_VER(12, 70), IP_VER(12, 74)))
-		pg_enable =
-			GEN9_MEDIA_PG_ENABLE |
-			GEN11_MEDIA_SAMPLER_PG_ENABLE;
-	else
-		pg_enable =
-			GEN9_RENDER_PG_ENABLE |
-			GEN9_MEDIA_PG_ENABLE |
-			GEN11_MEDIA_SAMPLER_PG_ENABLE;
+	pg_enable =
+		GEN9_RENDER_PG_ENABLE |
+		GEN9_MEDIA_PG_ENABLE |
+		GEN11_MEDIA_SAMPLER_PG_ENABLE;
 
 	if (GRAPHICS_VER(gt->i915) >= 12 && !IS_DG1(gt->i915)) {
 		for (i = 0; i < I915_MAX_VCS; i++)

drivers/gpu/drm/i915/selftests/i915_selftest.c

@@ -23,7 +23,9 @@
 
 #include <linux/random.h>
 
+#include "gt/intel_gt.h"
 #include "gt/intel_gt_pm.h"
+#include "gt/intel_gt_regs.h"
 #include "gt/uc/intel_gsc_fw.h"
 
 #include "i915_driver.h"
@@ -253,11 +255,27 @@ int i915_mock_selftests(void)
 int i915_live_selftests(struct pci_dev *pdev)
 {
 	struct drm_i915_private *i915 = pdev_to_i915(pdev);
+	struct intel_uncore *uncore = &i915->uncore;
 	int err;
+	u32 pg_enable;
+	intel_wakeref_t wakeref;
 
 	if (!i915_selftest.live)
 		return 0;
 
+	/*
+	 * FIXME Disable render powergating, this is temporary wa and should be removed
+	 * after fixing real cause of forcewake timeouts.
+	 */
+	with_intel_runtime_pm(uncore->rpm, wakeref) {
+		if (IS_GFX_GT_IP_RANGE(to_gt(i915), IP_VER(12, 00), IP_VER(12, 74))) {
+			pg_enable = intel_uncore_read(uncore, GEN9_PG_ENABLE);
+			if (pg_enable & GEN9_RENDER_PG_ENABLE)
+				intel_uncore_write_fw(uncore, GEN9_PG_ENABLE,
+						      pg_enable & ~GEN9_RENDER_PG_ENABLE);
+		}
+	}
+
 	__wait_gsc_proxy_completed(i915);
 	__wait_gsc_huc_load_completed(i915);