svn commit: r355195 - stable/12/sys/dev/ioat

[Alexander Motin]

Author: mav
Date: Fri Nov 29 00:25:39 2019
New Revision: 355195
URL: https://svnweb.freebsd.org/changeset/base/355195

Log:
  MFC r354753: Initialize *comp_update with valid value.
  
  I've noticed that sometimes with enabled DMAR initial write from device
  to this address is somehow getting delayed, triggering assertion due to
  zero default being invalid.

Modified:
  stable/12/sys/dev/ioat/ioat.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/dev/ioat/ioat.c
==============================================================================
--- stable/12/sys/dev/ioat/ioat.c	Thu Nov 28 23:34:23 2019	(r355194)
+++ stable/12/sys/dev/ioat/ioat.c	Fri Nov 29 00:25:39 2019	(r355195)
@@ -545,10 +545,9 @@ ioat3_attach(device_t device)
 		dma_hw_desc->next = RING_PHYS_ADDR(ioat, i + 1);
 	}
 
-	ioat->head = 0;
-	ioat->tail = 0;
-	ioat->last_seen = 0;
-	*ioat->comp_update = 0;
+	ioat->tail = ioat->head = 0;
+	*ioat->comp_update = ioat->last_seen =
+	    RING_PHYS_ADDR(ioat, ioat->tail - 1);
 	return (0);
 }
 
@@ -1591,8 +1590,8 @@ ioat_reset_hw(struct ioat_softc *ioat)
 	 * at zero as well.
 	 */
 	ioat->tail = ioat->head = 0;
-	ioat->last_seen = 0;
-	*ioat->comp_update = 0;
+	*ioat->comp_update = ioat->last_seen =
+	    RING_PHYS_ADDR(ioat, ioat->tail - 1);
 
 	ioat_write_chanctrl(ioat, IOAT_CHANCTRL_RUN);
 	ioat_write_chancmp(ioat, ioat->comp_update_bus_addr);