drm/xe: hold mem_access.ref for CT fast-path

Just checking xe_device_mem_access_ongoing() is not enough, we also need
to hold the reference otherwise the ref can transition from 1 -> 0 as we
enter g2h_read(), leading to warnings. While we can't do a full rpm sync
in the IRQ, we can keep the device awake if the ref is non-zero.
Introduce a new helper for this and set it to work in for the CT
fast-path.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 6249eef752c58a11cb69497562163e7eb0f2c406..bd2e10952989fbb02148bfed8b7bc6725bab42d6 100644 (file)
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -364,6 +364,11 @@ u32 xe_device_ccs_bytes(struct xe_device *xe, u64 size)
                DIV_ROUND_UP(size, NUM_BYTES_PER_CCS_BYTE) : 0;
 }
 
+bool xe_device_mem_access_get_if_ongoing(struct xe_device *xe)
+{
+       return atomic_inc_not_zero(&xe->mem_access.ref);
+}
+
 void xe_device_mem_access_get(struct xe_device *xe)
 {
        bool resumed = xe_pm_runtime_resume_if_suspended(xe);

diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
index 779f71d066e6e20641b1d3560ca00b349c4bbedc..8e01bbadb1498caa04a27f363a19be04c9db2898 100644 (file)
--- a/drivers/gpu/drm/xe/xe_device.h
+++ b/drivers/gpu/drm/xe/xe_device.h
@@ -138,6 +138,7 @@ static inline struct xe_force_wake * gt_to_fw(struct xe_gt *gt)
 }
 
 void xe_device_mem_access_get(struct xe_device *xe);
+bool xe_device_mem_access_get_if_ongoing(struct xe_device *xe);
 void xe_device_mem_access_put(struct xe_device *xe);
 
 static inline bool xe_device_mem_access_ongoing(struct xe_device *xe)

diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
index e71d069158dcaa735e888389fa0fb015607ce365..dcce6ed34370bd5333335afa7c9a96c214636c05 100644 (file)
--- a/drivers/gpu/drm/xe/xe_guc_ct.c
+++ b/drivers/gpu/drm/xe/xe_guc_ct.c
@@ -1044,7 +1044,8 @@ void xe_guc_ct_fast_path(struct xe_guc_ct *ct)
        struct xe_device *xe = ct_to_xe(ct);
        int len;
 
-       if (!xe_device_in_fault_mode(xe) || !xe_device_mem_access_ongoing(xe))
+       if (!xe_device_in_fault_mode(xe) ||
+           !xe_device_mem_access_get_if_ongoing(xe))
                return;
 
        spin_lock(&ct->fast_lock);
@@ -1054,6 +1055,8 @@ void xe_guc_ct_fast_path(struct xe_guc_ct *ct)
                        g2h_fast_path(ct, ct->fast_msg, len);
        } while (len > 0);
        spin_unlock(&ct->fast_lock);
+
+       xe_device_mem_access_put(xe);
 }
 
 /* Returns less than zero on error, 0 on done, 1 on more available */