From 0b1b4d8571e26046bef016c1cf31720c3b7fa8c0 Mon Sep 17 00:00:00 2001
From: Bjorn Helgaas <bjorn.helgaas@hp.com>
Date: Wed, 14 Nov 2007 16:59:57 -0800
Subject: [PATCH] --- yaml --- r: 73711 b: refs/heads/master c:
 9626f1f117be21b6e4b7a1cb49814fc065dd3d2d h: refs/heads/master i:   73709:
 69336228e526a849b8ee479e337630ba56b7fb5c   73707:
 7c419e92d1fe4c920f991883581ea6b70e505d20   73703:
 52775f32ec5cdf2db6ad38160f8a091d41ad4702   73695:
 816f3dfaf83b2e42c1878c001cbb2e13071f2419 v: v3

---
 [refs]                            |  2 +-
 trunk/drivers/char/rtc.c          | 36 +++++++++++++++++++++++++------
 trunk/include/linux/mc146818rtc.h |  3 +++
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/[refs] b/[refs]
index 5fb988e97d93..a54bd14abefb 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4c06be10c790008aa2b2d19df2872ff39990b7bd
+refs/heads/master: 9626f1f117be21b6e4b7a1cb49814fc065dd3d2d
diff --git a/trunk/drivers/char/rtc.c b/trunk/drivers/char/rtc.c
index a162e1b3d5d3..0c66b802736a 100644
--- a/trunk/drivers/char/rtc.c
+++ b/trunk/drivers/char/rtc.c
@@ -918,12 +918,29 @@ static const struct file_operations rtc_proc_fops = {
 };
 #endif
 
+static resource_size_t rtc_size;
+
+static struct resource * __init rtc_request_region(resource_size_t size)
+{
+	struct resource *r;
+
+	if (RTC_IOMAPPED)
+		r = request_region(RTC_PORT(0), size, "rtc");
+	else
+		r = request_mem_region(RTC_PORT(0), size, "rtc");
+
+	if (r)
+		rtc_size = size;
+
+	return r;
+}
+
 static void rtc_release_region(void)
 {
 	if (RTC_IOMAPPED)
-		release_region(RTC_PORT(0), RTC_IO_EXTENT);
+		release_region(RTC_PORT(0), rtc_size);
 	else
-		release_mem_region(RTC_PORT(0), RTC_IO_EXTENT);
+		release_mem_region(RTC_PORT(0), rtc_size);
 }
 
 static int __init rtc_init(void)
@@ -976,10 +993,17 @@ static int __init rtc_init(void)
 	}
 no_irq:
 #else
-	if (RTC_IOMAPPED)
-		r = request_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc");
-	else
-		r = request_mem_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc");
+	r = rtc_request_region(RTC_IO_EXTENT);
+
+	/*
+	 * If we've already requested a smaller range (for example, because
+	 * PNPBIOS or ACPI told us how the device is configured), the request
+	 * above might fail because it's too big.
+	 *
+	 * If so, request just the range we actually use.
+	 */
+	if (!r)
+		r = rtc_request_region(RTC_IO_EXTENT_USED);
 	if (!r) {
 #ifdef RTC_IRQ
 		rtc_has_irq = 0;
diff --git a/trunk/include/linux/mc146818rtc.h b/trunk/include/linux/mc146818rtc.h
index 580b3f4956ee..2f4e957af656 100644
--- a/trunk/include/linux/mc146818rtc.h
+++ b/trunk/include/linux/mc146818rtc.h
@@ -109,8 +109,11 @@ struct cmos_rtc_board_info {
 #ifndef ARCH_RTC_LOCATION	/* Override by <asm/mc146818rtc.h>? */
 
 #define RTC_IO_EXTENT	0x8
+#define RTC_IO_EXTENT_USED	0x2
 #define RTC_IOMAPPED	1	/* Default to I/O mapping. */
 
+#else
+#define RTC_IO_EXTENT_USED      RTC_IO_EXTENT
 #endif /* ARCH_RTC_LOCATION */
 
 #endif /* _MC146818RTC_H */