[PATCH v2 5/6] drm/xe/guc: Wait before retrying sending H2G

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

We shall resend H2G message after receiving NO_RESPONSE_RETRY reply,
but since GuC dropped that H2G due to some interim state, we should
give it a little time to stabilize. Wait before sending the same H2G
again, start with 1ms delay, then increase exponentially to 256ms.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
---
v2: use xe_sleep_exponential_ms helper (Michal)
    don't wait full 1s (Matt)
---
 drivers/gpu/drm/xe/xe_guc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
index 2a3b057fc828..231844bce1e0 100644
--- a/drivers/gpu/drm/xe/xe_guc.c
+++ b/drivers/gpu/drm/xe/xe_guc.c
@@ -40,6 +40,7 @@
 #include "xe_memirq.h"
 #include "xe_mmio.h"
 #include "xe_platform_types.h"
+#include "xe_sleep.h"
 #include "xe_sriov.h"
 #include "xe_sriov_pf_migration.h"
 #include "xe_uc.h"
@@ -1397,6 +1398,7 @@ int xe_guc_mmio_send_recv(struct xe_guc *guc, const u32 *request,
 	struct xe_reg reply_reg = xe_gt_is_media_type(gt) ?
 		MED_VF_SW_FLAG(0) : VF_SW_FLAG(0);
 	const u32 LAST_INDEX = VF_SW_FLAG_COUNT - 1;
+	unsigned int sleep_period_ms = 1;
 	bool lost = false;
 	u32 header;
 	int ret;
@@ -1479,6 +1481,8 @@ int xe_guc_mmio_send_recv(struct xe_guc *guc, const u32 *request,
 
 		xe_gt_dbg(gt, "GuC mmio request %#x: retrying, reason %#x\n",
 			  request[0], reason);
+
+		xe_sleep_exponential_ms(&sleep_period_ms, 256);
 		goto retry;
 	}
 
-- 
2.47.1