[PATCH 1/1] drm/xe: enable lite restore

[fei.yang at intel.com]

From: Fei Yang <fei.yang at intel.com>

The lite restore is a performance improvement feature which avoids
unnecessary context switch (flush, save and rstore) if the incoming
context has a ContextID matching that of the outgoing context. The
scheduling is done by the Guc firmware, so on the driver side it's
just a matter of setting corresponding GuC_CTL_FEATURE flag.
This is supposed to be enabled by default, thus the flag is set
unconditionally.

Signed-off-by: Fei Yang <fei.yang at intel.com>
Reviewed-by: John Harrison <John.C.Harrison at Intel.com>
---
 drivers/gpu/drm/xe/xe_guc.c      | 2 +-
 drivers/gpu/drm/xe/xe_guc_fwif.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
index 76437d42b8a1..04e50eb6e506 100644
--- a/drivers/gpu/drm/xe/xe_guc.c
+++ b/drivers/gpu/drm/xe/xe_guc.c
@@ -70,7 +70,7 @@ static u32 guc_ctl_debug_flags(struct xe_guc *guc)
 
 static u32 guc_ctl_feature_flags(struct xe_guc *guc)
 {
-	u32 flags = 0;
+	u32 flags = GUC_CTL_ENABLE_LITE_RESTORE;
 
 	if (!guc_to_xe(guc)->info.skip_guc_pc)
 		flags |= GUC_CTL_ENABLE_SLPC;
diff --git a/drivers/gpu/drm/xe/xe_guc_fwif.h b/drivers/gpu/drm/xe/xe_guc_fwif.h
index 01e3ab590c3a..08ffe59f22fa 100644
--- a/drivers/gpu/drm/xe/xe_guc_fwif.h
+++ b/drivers/gpu/drm/xe/xe_guc_fwif.h
@@ -105,6 +105,7 @@ struct guc_update_exec_queue_policy {
 
 #define GUC_CTL_FEATURE			2
 #define   GUC_CTL_ENABLE_SLPC		BIT(2)
+#define   GUC_CTL_ENABLE_LITE_RESTORE	BIT(4)
 #define   GUC_CTL_DISABLE_SCHEDULER	BIT(14)
 
 #define GUC_CTL_DEBUG			3
-- 
2.25.1