* | | | - _`GUC_CTB_STATUS_OVERFLOW` = 1 (head/tail too large) |
* | | | - _`GUC_CTB_STATUS_UNDERFLOW` = 2 (truncated message) |
* | | | - _`GUC_CTB_STATUS_MISMATCH` = 4 (head/tail modified) |
+ * | | | - _`GUC_CTB_STATUS_UNUSED` = 8 (CTB is not in use) |
* +---+-------+--------------------------------------------------------------+
* |...| | RESERVED = MBZ |
* +---+-------+--------------------------------------------------------------+
u32 tail;
u32 status;
#define GUC_CTB_STATUS_NO_ERROR 0
-#define GUC_CTB_STATUS_OVERFLOW (1 << 0)
-#define GUC_CTB_STATUS_UNDERFLOW (1 << 1)
-#define GUC_CTB_STATUS_MISMATCH (1 << 2)
+#define GUC_CTB_STATUS_OVERFLOW BIT(0)
+#define GUC_CTB_STATUS_UNDERFLOW BIT(1)
+#define GUC_CTB_STATUS_MISMATCH BIT(2)
+#define GUC_CTB_STATUS_UNUSED BIT(3)
u32 reserved[13];
} __packed;
static_assert(sizeof(struct guc_ct_buffer_desc) == 64);
if (unlikely(ctb->broken))
return -EPIPE;
- if (unlikely(desc->status))
- goto corrupted;
+ if (unlikely(desc->status)) {
+ u32 status = desc->status;
+
+ if (status & GUC_CTB_STATUS_UNUSED) {
+ /*
+ * Potentially valid if a CLIENT_RESET request resulted in
+ * contexts/engines being reset. But should never happen as
+ * no contexts should be active when CLIENT_RESET is sent.
+ */
+ CT_ERROR(ct, "Unexpected G2H after GuC has stopped!\n");
+ status &= ~GUC_CTB_STATUS_UNUSED;
+ }
+
+ if (status)
+ goto corrupted;
+ }
GEM_BUG_ON(head > size);