svn commit: r354753 - head/sys/dev/ioat

[Alexander Motin]

Author: mav
Date: Fri Nov 15 23:01:09 2019
New Revision: 354753
URL: https://svnweb.freebsd.org/changeset/base/354753

Log:
  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.
  
  MFC after:	2 weeks
  Sponsored by:	iXsystems, Inc.

Modified:
  head/sys/dev/ioat/ioat.c

Modified: head/sys/dev/ioat/ioat.c
==============================================================================
--- head/sys/dev/ioat/ioat.c	Fri Nov 15 22:47:59 2019	(r354752)
+++ head/sys/dev/ioat/ioat.c	Fri Nov 15 23:01:09 2019	(r354753)
@@ -642,10 +642,9 @@ 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);
 }
 
@@ -1751,8 +1750,8 @@ 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);