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Date:      Mon, 16 May 2016 21:33:31 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r299977 - head/sys/dev/acpica/Osd
Message-ID:  <201605162133.u4GLXV3S048795@repo.freebsd.org>
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Author: jhb
Date: Mon May 16 21:33:31 2016
New Revision: 299977
URL: https://svnweb.freebsd.org/changeset/base/299977

Log:
  Use polling spin loops for timeouts during early boot.
  
  Some ACPI operations such as mutex acquires and event waits accept a
  timeout.  The ACPI OSD layer implements these timeouts by using regular
  sleep timeouts.  However, this doesn't work during early boot before
  event timers are setup.  Instead, use polling combined with DELAY()
  to spin.
  
  This fixes booting on upcoming Intel systems with Kaby Lake processors.
  
  Tested by:	"Jeffrey E Pieper" <jeffrey.e.pieper@intel.com>
  Reviewed by:	jimharris
  MFC after:	1 week

Modified:
  head/sys/dev/acpica/Osd/OsdSynch.c

Modified: head/sys/dev/acpica/Osd/OsdSynch.c
==============================================================================
--- head/sys/dev/acpica/Osd/OsdSynch.c	Mon May 16 20:26:30 2016	(r299976)
+++ head/sys/dev/acpica/Osd/OsdSynch.c	Mon May 16 21:33:31 2016	(r299977)
@@ -188,6 +188,23 @@ AcpiOsWaitSemaphore(ACPI_SEMAPHORE Handl
 		}
 		break;
 	default:
+		if (cold) {
+			/*
+			 * Just spin polling the semaphore once a
+			 * millisecond.
+			 */
+			while (!ACPISEM_AVAIL(as, Units)) {
+				if (Timeout == 0) {
+					status = AE_TIME;
+					break;
+				}
+				Timeout--;
+				mtx_unlock(&as->as_lock);
+				DELAY(1000);
+				mtx_lock(&as->as_lock);
+			}
+			break;
+		}
 		tmo = timeout2hz(Timeout);
 		while (!ACPISEM_AVAIL(as, Units)) {
 			prevtick = ticks;
@@ -381,6 +398,23 @@ AcpiOsAcquireMutex(ACPI_MUTEX Handle, UI
 		}
 		break;
 	default:
+		if (cold) {
+			/*
+			 * Just spin polling the mutex once a
+			 * millisecond.
+			 */
+			while (!ACPIMTX_AVAIL(am)) {
+				if (Timeout == 0) {
+					status = AE_TIME;
+					break;
+				}
+				Timeout--;
+				mtx_unlock(&am->am_lock);
+				DELAY(1000);
+				mtx_lock(&am->am_lock);
+			}
+			break;
+		}
 		tmo = timeout2hz(Timeout);
 		while (!ACPIMTX_AVAIL(am)) {
 			prevtick = ticks;

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