From 6bb8d8aebc305fbbac9488f4d1c792f35cbe2375 Mon Sep 17 00:00:00 2001
From: Bjorn Helgaas <bjorn.helgaas@hp.com>
Date: Tue, 26 Oct 2010 15:41:44 -0600
Subject: [PATCH] --- yaml --- r: 219566 b: refs/heads/master c:
 dc9887dc02e37bcf83f4e792aa14b07782ef54cf h: refs/heads/master v: v3

---
 [refs]                    |  2 +-
 trunk/arch/x86/pci/i386.c | 17 +++++++++++------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/[refs] b/[refs]
index a583b35997e1..b92512bccf56 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b126b4703afa4010b161784a43650337676dd03b
+refs/heads/master: dc9887dc02e37bcf83f4e792aa14b07782ef54cf
diff --git a/trunk/arch/x86/pci/i386.c b/trunk/arch/x86/pci/i386.c
index 55253095be84..826140af3c3c 100644
--- a/trunk/arch/x86/pci/i386.c
+++ b/trunk/arch/x86/pci/i386.c
@@ -65,16 +65,21 @@ pcibios_align_resource(void *data, const struct resource *res,
 			resource_size_t size, resource_size_t align)
 {
 	struct pci_dev *dev = data;
-	resource_size_t start = res->start;
+	resource_size_t start = round_down(res->end - size + 1, align);
 
 	if (res->flags & IORESOURCE_IO) {
-		if (skip_isa_ioresource_align(dev))
-			return start;
-		if (start & 0x300)
-			start = (start + 0x3ff) & ~0x3ff;
+
+		/*
+		 * If we're avoiding ISA aliases, the largest contiguous I/O
+		 * port space is 256 bytes.  Clearing bits 9 and 10 preserves
+		 * all 256-byte and smaller alignments, so the result will
+		 * still be correctly aligned.
+		 */
+		if (!skip_isa_ioresource_align(dev))
+			start &= ~0x300;
 	} else if (res->flags & IORESOURCE_MEM) {
 		if (start < BIOS_END)
-			start = BIOS_END;
+			start = res->end;	/* fail; no space */
 	}
 	return start;
 }