Unverified Commit ac1317df authored Dec 22, 2025 by Jonathan Cavitt Committed by Rodrigo Vivi Dec 23, 2025

drm/xe/guc: READ/WRITE_ONCE ct->state



Use READ_ONCE and WRITE_ONCE when operating on ct->state
to prevent the compiler form ignoring important modifications
to its value.

Suggested-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251222201957.63245-6-jonathan.cavitt@intel.com


Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

parent b5179dbd

drivers/gpu/drm/xe/xe_guc_ct.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -529,7 +529,12 @@ static void guc_ct_change_state(struct xe_guc_ct *ct,
		if (ct->g2h_outstanding)
		xe_pm_runtime_put(ct_to_xe(ct));
		ct->g2h_outstanding = 0;
		ct->state = state;

		/*
		* WRITE_ONCE pairs with READ_ONCEs in xe_guc_ct_initialized and
		* xe_guc_ct_enabled.
		*/
		WRITE_ONCE(ct->state, state);

		xe_gt_dbg(gt, "GuC CT communication channel %s\n",
		state == XE_GUC_CT_STATE_STOPPED ? "stopped" :

drivers/gpu/drm/xe/xe_guc_ct.h

+4 −2

Original line number	Diff line number	Diff line
		@@ -30,12 +30,14 @@ void xe_guc_ct_print(struct xe_guc_ct ct, struct drm_printer p, bool want_ctb)

		static inline bool xe_guc_ct_initialized(struct xe_guc_ct *ct)
		{
		return ct->state != XE_GUC_CT_STATE_NOT_INITIALIZED;
		/* READ_ONCE pairs with WRITE_ONCE in guc_ct_change_state. */
		return READ_ONCE(ct->state) != XE_GUC_CT_STATE_NOT_INITIALIZED;
		}

		static inline bool xe_guc_ct_enabled(struct xe_guc_ct *ct)
		{
		return ct->state == XE_GUC_CT_STATE_ENABLED;
		/* READ_ONCE pairs with WRITE_ONCE in guc_ct_change_state. */
		return READ_ONCE(ct->state) == XE_GUC_CT_STATE_ENABLED;
		}

		static inline void xe_guc_ct_irq_handler(struct xe_guc_ct *ct)