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authorRene Herman <rene.herman@gmail.com>2008-01-30 07:30:05 -0500
committerIngo Molnar <mingo@elte.hu>2008-01-30 07:30:05 -0500
commitb02aae9cf52956dfe1bec73f77f81a3d05d3902b (patch)
treece715a107c853960cc9541377aeae0ff31ac25f7 /arch
parent4c6b8b4d62fb4cb843c32db71e0a8301039908f3 (diff)
x86: provide a DMI based port 0x80 I/O delay override.
x86: provide a DMI based port 0x80 I/O delay override. Certain (HP) laptops experience trouble from our port 0x80 I/O delay writes. This patch provides for a DMI based switch to the "alternate diagnostic port" 0xed (as used by some BIOSes as well) for these. David P. Reed confirmed that port 0xed works for him and provides a proper delay. The symptoms of _not_ working are a hanging machine, with "hwclock" use being a direct trigger. Earlier versions of this attempted to simply use udelay(2), with the 2 being a value tested to be a nicely conservative upper-bound with help from many on the linux-kernel mailinglist but that approach has two problems. First, pre-loops_per_jiffy calibration (which is post PIT init while some implementations of the PIT are actually one of the historically problematic devices that need the delay) udelay() isn't particularly well-defined. We could initialise loops_per_jiffy conservatively (and based on CPU family so as to not unduly delay old machines) which would sort of work, but... Second, delaying isn't the only effect that a write to port 0x80 has. It's also a PCI posting barrier which some devices may be explicitly or implicitly relying on. Alan Cox did a survey and found evidence that additionally some drivers may be racy on SMP without the bus locking outb. Switching to an inb() makes the timing too unpredictable and as such, this DMI based switch should be the safest approach for now. Any more invasive changes should get more rigid testing first. It's moreover only very few machines with the problem and a DMI based hack seems to fit that situation. This also introduces a command-line parameter "io_delay" to override the DMI based choice again: io_delay=<standard|alternate> where "standard" means using the standard port 0x80 and "alternate" port 0xed. This retains the udelay method as a config (CONFIG_UDELAY_IO_DELAY) and command-line ("io_delay=udelay") choice for testing purposes as well. This does not change the io_delay() in the boot code which is using the same port 0x80 I/O delay but those do not appear to be a problem as David P. Reed reported the problem was already gone after using the udelay version. He moreover reported that booting with "acpi=off" also fixed things and seeing as how ACPI isn't touched until after this DMI based I/O port switch I believe it's safe to leave the ones in the boot code be. The DMI strings from David's HP Pavilion dv9000z are in there already and we need to get/verify the DMI info from other machines with the problem, notably the HP Pavilion dv6000z. This patch is partly based on earlier patches from Pavel Machek and David P. Reed. Signed-off-by: Rene Herman <rene.herman@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig.debug9
-rw-r--r--arch/x86/boot/compressed/misc_32.c8
-rw-r--r--arch/x86/boot/compressed/misc_64.c8
-rw-r--r--arch/x86/kernel/Makefile_322
-rw-r--r--arch/x86/kernel/Makefile_642
-rw-r--r--arch/x86/kernel/io_delay.c106
-rw-r--r--arch/x86/kernel/setup_32.c2
-rw-r--r--arch/x86/kernel/setup_64.c2
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
112 Add a simple leak tracer to the IOMMU code. This is useful when you 112 Add a simple leak tracer to the IOMMU code. This is useful when you
113 are debugging a buggy device driver that leaks IOMMU mappings. 113 are debugging a buggy device driver that leaks IOMMU mappings.
114 114
115config UDELAY_IO_DELAY
116 bool "Delay I/O through udelay instead of outb"
117 depends on DEBUG_KERNEL
118 help
119 Make inb_p/outb_p use udelay() based delays by default. Please note
120 that udelay() does not have the same bus-level side-effects that
121 the normal outb based delay does meaning this could cause drivers
122 to change behaviour and/or bugs to surface.
123
115endmenu 124endmenu
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)
276 RM_SCREEN_INFO.orig_y = y; 276 RM_SCREEN_INFO.orig_y = y;
277 277
278 pos = (x + cols * y) * 2; /* Update cursor position */ 278 pos = (x + cols * y) * 2; /* Update cursor position */
279 outb_p(14, vidport); 279 outb(14, vidport);
280 outb_p(0xff & (pos >> 9), vidport+1); 280 outb(0xff & (pos >> 9), vidport+1);
281 outb_p(15, vidport); 281 outb(15, vidport);
282 outb_p(0xff & (pos >> 1), vidport+1); 282 outb(0xff & (pos >> 1), vidport+1);
283} 283}
284 284
285static void* memset(void* s, int c, unsigned n) 285static 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)
269 RM_SCREEN_INFO.orig_y = y; 269 RM_SCREEN_INFO.orig_y = y;
270 270
271 pos = (x + cols * y) * 2; /* Update cursor position */ 271 pos = (x + cols * y) * 2; /* Update cursor position */
272 outb_p(14, vidport); 272 outb(14, vidport);
273 outb_p(0xff & (pos >> 9), vidport+1); 273 outb(0xff & (pos >> 9), vidport+1);
274 outb_p(15, vidport); 274 outb(15, vidport);
275 outb_p(0xff & (pos >> 1), vidport+1); 275 outb(0xff & (pos >> 1), vidport+1);
276} 276}
277 277
278static void* memset(void* s, int c, unsigned n) 278static 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
8obj-y := process_32.o signal_32.o entry_32.o traps_32.o irq_32.o \ 8obj-y := process_32.o signal_32.o entry_32.o traps_32.o irq_32.o \
9 ptrace_32.o time_32.o ioport_32.o ldt_32.o setup_32.o i8259_32.o sys_i386_32.o \ 9 ptrace_32.o time_32.o ioport_32.o ldt_32.o setup_32.o i8259_32.o sys_i386_32.o \
10 pci-dma_32.o i386_ksyms_32.o i387_32.o bootflag.o e820_32.o\ 10 pci-dma_32.o i386_ksyms_32.o i387_32.o bootflag.o e820_32.o\
11 quirks.o i8237.o topology.o alternative.o i8253.o tsc_32.o 11 quirks.o i8237.o topology.o alternative.o i8253.o tsc_32.o io_delay.o
12 12
13obj-$(CONFIG_STACKTRACE) += stacktrace.o 13obj-$(CONFIG_STACKTRACE) += stacktrace.o
14obj-y += cpu/ 14obj-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 \
11 x8664_ksyms_64.o i387_64.o syscall_64.o vsyscall_64.o \ 11 x8664_ksyms_64.o i387_64.o syscall_64.o vsyscall_64.o \
12 setup64.o bootflag.o e820_64.o reboot_64.o quirks.o i8237.o \ 12 setup64.o bootflag.o e820_64.o reboot_64.o quirks.o i8237.o \
13 pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \ 13 pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \
14 i8253.o 14 i8253.o io_delay.o
15 15
16obj-$(CONFIG_STACKTRACE) += stacktrace.o 16obj-$(CONFIG_STACKTRACE) += stacktrace.o
17obj-y += cpu/ 17obj-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 @@
1/*
2 * I/O delay strategies for inb_p/outb_p
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/init.h>
7#include <linux/delay.h>
8#include <linux/dmi.h>
9#include <asm/io.h>
10
11/*
12 * Allow for a DMI based override of port 0x80 needed for certain HP laptops
13 */
14#define IO_DELAY_PORT_STD 0x80
15#define IO_DELAY_PORT_ALT 0xed
16
17static void standard_io_delay(void)
18{
19 asm volatile ("outb %%al, %0" : : "N" (IO_DELAY_PORT_STD));
20}
21
22static void alternate_io_delay(void)
23{
24 asm volatile ("outb %%al, %0" : : "N" (IO_DELAY_PORT_ALT));
25}
26
27/*
28 * 2 usecs is an upper-bound for the outb delay but note that udelay doesn't
29 * have the bus-level side-effects that outb does
30 */
31#define IO_DELAY_USECS 2
32
33/*
34 * High on a hill was a lonely goatherd
35 */
36static void udelay_io_delay(void)
37{
38 udelay(IO_DELAY_USECS);
39}
40
41#ifndef CONFIG_UDELAY_IO_DELAY
42static void (*io_delay)(void) = standard_io_delay;
43#else
44static void (*io_delay)(void) = udelay_io_delay;
45#endif
46
47/*
48 * Paravirt wants native_io_delay to be a constant.
49 */
50void native_io_delay(void)
51{
52 io_delay();
53}
54EXPORT_SYMBOL(native_io_delay);
55
56#ifndef CONFIG_UDELAY_IO_DELAY
57static int __init dmi_alternate_io_delay_port(const struct dmi_system_id *id)
58{
59 printk(KERN_NOTICE "%s: using alternate I/O delay port\n", id->ident);
60 io_delay = alternate_io_delay;
61 return 0;
62}
63
64static struct dmi_system_id __initdata alternate_io_delay_port_dmi_table[] = {
65 {
66 .callback = dmi_alternate_io_delay_port,
67 .ident = "HP Pavilion dv9000z",
68 .matches = {
69 DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
70 DMI_MATCH(DMI_BOARD_NAME, "30B9")
71 }
72 },
73 {
74 }
75};
76
77static int __initdata io_delay_override;
78
79void __init io_delay_init(void)
80{
81 if (!io_delay_override)
82 dmi_check_system(alternate_io_delay_port_dmi_table);
83}
84#endif
85
86static int __init io_delay_param(char *s)
87{
88 if (!s)
89 return -EINVAL;
90
91 if (!strcmp(s, "standard"))
92 io_delay = standard_io_delay;
93 else if (!strcmp(s, "alternate"))
94 io_delay = alternate_io_delay;
95 else if (!strcmp(s, "udelay"))
96 io_delay = udelay_io_delay;
97 else
98 return -EINVAL;
99
100#ifndef CONFIG_UDELAY_IO_DELAY
101 io_delay_override = 1;
102#endif
103 return 0;
104}
105
106early_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)
648 648
649 dmi_scan_machine(); 649 dmi_scan_machine();
650 650
651 io_delay_init();;
652
651#ifdef CONFIG_X86_GENERICARCH 653#ifdef CONFIG_X86_GENERICARCH
652 generic_apic_probe(); 654 generic_apic_probe();
653#endif 655#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)
311 311
312 dmi_scan_machine(); 312 dmi_scan_machine();
313 313
314 io_delay_init();
315
314#ifdef CONFIG_SMP 316#ifdef CONFIG_SMP
315 /* setup to use the static apicid table during kernel startup */ 317 /* setup to use the static apicid table during kernel startup */
316 x86_cpu_to_apicid_ptr = (void *)&x86_cpu_to_apicid_init; 318 x86_cpu_to_apicid_ptr = (void *)&x86_cpu_to_apicid_init;