8 files changed, 129 insertions, 10 deletions

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 761ca7b5f120..40aba670fb37 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -112,4 +112,13 @@ config IOMMU_LEAK
           Add a simple leak tracer to the IOMMU code. This is useful when you
           are debugging a buggy device driver that leaks IOMMU mappings.
 
+config UDELAY_IO_DELAY
+        bool "Delay I/O through udelay instead of outb"
+        depends on DEBUG_KERNEL
+        help
+          Make inb_p/outb_p use udelay() based delays by default. Please note
+          that udelay() does not have the same bus-level side-effects that
+          the normal outb based delay does meaning this could cause drivers
+          to change behaviour and/or bugs to surface.
+
 endmenu
diff --git a/arch/x86/boot/compressed/misc_32.c b/arch/x86/boot/compressed/misc_32.c
index b74d60d1b2fa..288e16283ef9 100644
--- a/arch/x86/boot/compressed/misc_32.c
+++ b/arch/x86/boot/compressed/misc_32.c
@@ -276,10 +276,10 @@ static void putstr(const char *s)
         RM_SCREEN_INFO.orig_y = y;
 
         pos = (x + cols * y) * 2;       /* Update cursor position */
-        outb_p(14, vidport);
-        outb_p(0xff & (pos >> 9), vidport+1);
-        outb_p(15, vidport);
-        outb_p(0xff & (pos >> 1), vidport+1);
+        outb(14, vidport);
+        outb(0xff & (pos >> 9), vidport+1);
+        outb(15, vidport);
+        outb(0xff & (pos >> 1), vidport+1);
 }
 
 static void* memset(void* s, int c, unsigned n)
diff --git a/arch/x86/boot/compressed/misc_64.c b/arch/x86/boot/compressed/misc_64.c
index 6ea015aa65e4..43e5fcc37be9 100644
--- a/arch/x86/boot/compressed/misc_64.c
+++ b/arch/x86/boot/compressed/misc_64.c
@@ -269,10 +269,10 @@ static void putstr(const char *s)
         RM_SCREEN_INFO.orig_y = y;
 
         pos = (x + cols * y) * 2;       /* Update cursor position */
-        outb_p(14, vidport);
-        outb_p(0xff & (pos >> 9), vidport+1);
-        outb_p(15, vidport);
-        outb_p(0xff & (pos >> 1), vidport+1);
+        outb(14, vidport);
+        outb(0xff & (pos >> 9), vidport+1);
+        outb(15, vidport);
+        outb(0xff & (pos >> 1), vidport+1);
 }
 
 static void* memset(void* s, int c, unsigned n)
diff --git a/arch/x86/kernel/Makefile_32 b/arch/x86/kernel/Makefile_32
index a7bc93c27662..0cc1981d1e38 100644
--- a/arch/x86/kernel/Makefile_32
+++ b/arch/x86/kernel/Makefile_32
@@ -8,7 +8,7 @@ CPPFLAGS_vmlinux.lds += -Ui386
 obj-y   := process_32.o signal_32.o entry_32.o traps_32.o irq_32.o \
                 ptrace_32.o time_32.o ioport_32.o ldt_32.o setup_32.o i8259_32.o sys_i386_32.o \
                 pci-dma_32.o i386_ksyms_32.o i387_32.o bootflag.o e820_32.o\
-                quirks.o i8237.o topology.o alternative.o i8253.o tsc_32.o
+                quirks.o i8237.o topology.o alternative.o i8253.o tsc_32.o io_delay.o
 
 obj-$(CONFIG_STACKTRACE)        += stacktrace.o
 obj-y                           += cpu/
diff --git a/arch/x86/kernel/Makefile_64 b/arch/x86/kernel/Makefile_64
index 5a88890d8ee9..08a68f0d8fda 100644
--- a/arch/x86/kernel/Makefile_64
+++ b/arch/x86/kernel/Makefile_64
@@ -11,7 +11,7 @@ obj-y	:= process_64.o signal_64.o entry_64.o traps_64.o irq_64.o \
                 x8664_ksyms_64.o i387_64.o syscall_64.o vsyscall_64.o \
                 setup64.o bootflag.o e820_64.o reboot_64.o quirks.o i8237.o \
                 pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \
-                i8253.o
+                i8253.o io_delay.o
 
 obj-$(CONFIG_STACKTRACE)        += stacktrace.o
 obj-y                           += cpu/
diff --git a/arch/x86/kernel/io_delay.c b/arch/x86/kernel/io_delay.c
new file mode 100644
index 000000000000..4d955e74b974
--- /dev/null
+++ b/arch/x86/kernel/io_delay.c
@@ -0,0 +1,106 @@
+/*
+ * I/O delay strategies for inb_p/outb_p
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/dmi.h>
+#include <asm/io.h>
+
+/*
+ * Allow for a DMI based override of port 0x80 needed for certain HP laptops
+ */
+#define IO_DELAY_PORT_STD 0x80
+#define IO_DELAY_PORT_ALT 0xed
+
+static void standard_io_delay(void)
+{
+        asm volatile ("outb %%al, %0" : : "N" (IO_DELAY_PORT_STD));
+}
+
+static void alternate_io_delay(void)
+{
+        asm volatile ("outb %%al, %0" : : "N" (IO_DELAY_PORT_ALT));
+}
+
+/*
+ * 2 usecs is an upper-bound for the outb delay but note that udelay doesn't
+ * have the bus-level side-effects that outb does
+ */
+#define IO_DELAY_USECS 2
+
+/*
+ * High on a hill was a lonely goatherd
+ */
+static void udelay_io_delay(void)
+{
+        udelay(IO_DELAY_USECS);
+}
+
+#ifndef CONFIG_UDELAY_IO_DELAY
+static void (*io_delay)(void) = standard_io_delay;
+#else
+static void (*io_delay)(void) = udelay_io_delay;
+#endif
+
+/*
+ * Paravirt wants native_io_delay to be a constant.
+ */
+void native_io_delay(void)
+{
+        io_delay();
+}
+EXPORT_SYMBOL(native_io_delay);
+
+#ifndef CONFIG_UDELAY_IO_DELAY
+static int __init dmi_alternate_io_delay_port(const struct dmi_system_id *id)
+{
+        printk(KERN_NOTICE "%s: using alternate I/O delay port\n", id->ident);
+        io_delay = alternate_io_delay;
+        return 0;
+}
+
+static struct dmi_system_id __initdata alternate_io_delay_port_dmi_table[] = {
+        {
+                .callback       = dmi_alternate_io_delay_port,
+                .ident          = "HP Pavilion dv9000z",
+                .matches        = {
+                        DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
+                        DMI_MATCH(DMI_BOARD_NAME, "30B9")
+                }
+        },
+        {
+        }
+};
+
+static int __initdata io_delay_override;
+
+void __init io_delay_init(void)
+{
+        if (!io_delay_override)
+                dmi_check_system(alternate_io_delay_port_dmi_table);
+}
+#endif
+
+static int __init io_delay_param(char *s)
+{
+        if (!s)
+                return -EINVAL;
+
+        if (!strcmp(s, "standard"))
+                io_delay = standard_io_delay;
+        else if (!strcmp(s, "alternate"))
+                io_delay = alternate_io_delay;
+        else if (!strcmp(s, "udelay"))
+                io_delay = udelay_io_delay;
+        else
+                return -EINVAL;
+
+#ifndef CONFIG_UDELAY_IO_DELAY
+        io_delay_override = 1;
+#endif
+        return 0;
+}
+
+early_param("io_delay", io_delay_param);
diff --git a/arch/x86/kernel/setup_32.c b/arch/x86/kernel/setup_32.c
index 9c24b45b513c..51bdc0b1b72e 100644
--- a/arch/x86/kernel/setup_32.c
+++ b/arch/x86/kernel/setup_32.c
@@ -648,6 +648,8 @@ void __init setup_arch(char **cmdline_p)
 
         dmi_scan_machine();
 
+        io_delay_init();;
+
 #ifdef CONFIG_X86_GENERICARCH
         generic_apic_probe();
 #endif  
diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index 30d94d1d5f5f..ec976edf0399 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -311,6 +311,8 @@ void __init setup_arch(char **cmdline_p)
 
         dmi_scan_machine();
 
+        io_delay_init();
+
 #ifdef CONFIG_SMP
         /* setup to use the static apicid table during kernel startup */
         x86_cpu_to_apicid_ptr = (void *)&x86_cpu_to_apicid_init;