svn commit: r272606 - head/sys/dev/ahci

[Alexander Motin]

Author: mav
Date: Mon Oct  6 10:58:54 2014
New Revision: 272606
URL: https://svnweb.freebsd.org/changeset/base/272606

Log:
  Use r271207 optimization only for MSI-enabled HBAs.
  
  It was found that VirtualBox' AHCI does not allow nterrupt to be cleared
  before the interrupt status register is read, causing interrupt storm.
  
  AHCI specification allows to skip this register use when multi-vector MSI
  is enabled and so interrupting port is known.  For single-vector MSI that
  is not stated explicitly, but if the port is only one, it is obviously
  known too.

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

Modified: head/sys/dev/ahci/ahci.c
==============================================================================
--- head/sys/dev/ahci/ahci.c	Mon Oct  6 09:52:28 2014	(r272605)
+++ head/sys/dev/ahci/ahci.c	Mon Oct  6 10:58:54 2014	(r272606)
@@ -360,7 +360,7 @@ ahci_setup_interrupt(device_t dev)
 	for (i = 0; i < ctlr->numirqs; i++) {
 		ctlr->irqs[i].ctlr = ctlr;
 		ctlr->irqs[i].r_irq_rid = i + (ctlr->msi ? 1 : 0);
-		if (ctlr->channels == 1 && !ctlr->ccc)
+		if (ctlr->channels == 1 && !ctlr->ccc && ctlr->msi)
 			ctlr->irqs[i].mode = AHCI_IRQ_MODE_ONE;
 		else if (ctlr->numirqs == 1 || i >= ctlr->channels ||
 		    (ctlr->ccc && i == ctlr->cccv))