commit c83008ff40e95f89407807cb122127c5444b3bc4 Author: Rene Herman Date: Mon Dec 17 21:23:55 2007 +0100 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 still leaves: 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 various drivers are 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. An early boot parameter to make the choice manually (and override any possible DMI based decision) is also provided: io_delay=standard|alternate 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 tested by David P. Reed. 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 leaving the ones in the boot code be is safe. 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 diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 33121d6..ff66cf4 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -785,6 +785,13 @@ and is between 256 and 4096 characters. It is defined in the file for translation below 32 bit and if not available then look in the higher range. + io_delay= [X86-32,X86-64] I/O delay port + standard + Use the 0x80 standard I/O delay port (default) + alternate + Use the 0xed alternate I/O delay port + + Use the io7= [HW] IO7 for Marvel based alpha systems See comment before marvel_specify_io7 in arch/alpha/kernel/core_marvel.c. diff --git a/arch/x86/boot/compressed/misc_32.c b/arch/x86/boot/compressed/misc_32.c index b74d60d..288e162 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 6ea015a..43e5fcc 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 a7bc93c..0cc1981 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-$(CONFIG_STACKTRACE) += stacktrace.o obj-y += cpu/ diff --git a/arch/x86/kernel/Makefile_64 b/arch/x86/kernel/Makefile_64 index 5a88890..08a68f0 100644 --- a/arch/x86/kernel/Makefile_64 +++ b/arch/x86/kernel/Makefile_64 @@ -11,7 +11,7 @@ obj-y := process_64.o signal_64.o entry_64.o traps_64.o irq_64.o \ x8664_ksyms_64.o i387_64.o syscall_64.o vsyscall_64.o \ setup64.o bootflag.o e820_64.o reboot_64.o quirks.o i8237.o \ pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \ - i8253.o + i8253.o io_delay.o obj-$(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 0000000..5029e7a --- /dev/null +++ b/arch/x86/kernel/io_delay.c @@ -0,0 +1,69 @@ +/* + * I/O delay strategies for inb_p/outb_p + */ + +#include +#include +#include +#include +#include + +/* + * Allow for a DMI based override of port 0x80 + */ +#define IO_DELAY_PORT_STD 0x80 +#define IO_DELAY_PORT_ALT 0xed + +static unsigned short io_delay_port __read_mostly = IO_DELAY_PORT_STD; + +void native_io_delay(void) +{ + asm volatile ("outb %%al, %w0" : : "d" (io_delay_port)); +} +EXPORT_SYMBOL(native_io_delay); + +static int __init dmi_io_delay_port_alt(const struct dmi_system_id *id) +{ + printk(KERN_NOTICE "%s: using alternate I/O delay port\n", id->ident); + io_delay_port = IO_DELAY_PORT_ALT; + return 0; +} + +static struct dmi_system_id __initdata dmi_io_delay_port_alt_table[] = { + { + .callback = dmi_io_delay_port_alt, + .ident = "HP Pavilion dv9000z", + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"), + DMI_MATCH(DMI_BOARD_NAME, "30B9") + } + }, + { + } +}; + +static int __initdata io_delay_override; + +static int __init io_delay_param(char *s) +{ + if (!s) + return -EINVAL; + + if (!strcmp(s, "standard")) + io_delay_port = IO_DELAY_PORT_STD; + else if (!strcmp(s, "alternate")) + io_delay_port = IO_DELAY_PORT_ALT; + else + return -EINVAL; + + io_delay_override = 1; + return 0; +} + +early_param("io_delay", io_delay_param); + +void __init io_delay_init(void) +{ + if (!io_delay_override) + dmi_check_system(dmi_io_delay_port_alt_table); +} diff --git a/arch/x86/kernel/setup_32.c b/arch/x86/kernel/setup_32.c index e1e18c3..6c3a3b4 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 30d94d1..ec976ed 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; diff --git a/include/asm-x86/io_32.h b/include/asm-x86/io_32.h index fe881cd..690b8f4 100644 --- a/include/asm-x86/io_32.h +++ b/include/asm-x86/io_32.h @@ -250,10 +250,8 @@ static inline void flush_write_buffers(void) #endif /* __KERNEL__ */ -static inline void native_io_delay(void) -{ - asm volatile("outb %%al,$0x80" : : : "memory"); -} +extern void io_delay_init(void); +extern void native_io_delay(void); #if defined(CONFIG_PARAVIRT) #include diff --git a/include/asm-x86/io_64.h b/include/asm-x86/io_64.h index a037b07..b2d4994 100644 --- a/include/asm-x86/io_64.h +++ b/include/asm-x86/io_64.h @@ -35,13 +35,18 @@ * - Arnaldo Carvalho de Melo */ -#define __SLOW_DOWN_IO "\noutb %%al,$0x80" +extern void io_delay_init(void); +extern void native_io_delay(void); +static inline void slow_down_io(void) +{ + native_io_delay(); #ifdef REALLY_SLOW_IO -#define __FULL_SLOW_DOWN_IO __SLOW_DOWN_IO __SLOW_DOWN_IO __SLOW_DOWN_IO __SLOW_DOWN_IO -#else -#define __FULL_SLOW_DOWN_IO __SLOW_DOWN_IO + native_io_delay(); + native_io_delay(); + native_io_delay(); #endif +} /* * Talk about misusing macros.. @@ -50,21 +55,21 @@ static inline void out##s(unsigned x value, unsigned short port) { #define __OUT2(s,s1,s2) \ -__asm__ __volatile__ ("out" #s " %" s1 "0,%" s2 "1" +__asm__ __volatile__ ("out" #s " %" s1 "0,%" s2 "1" : : "a" (value), "Nd" (port)) #define __OUT(s,s1,x) \ -__OUT1(s,x) __OUT2(s,s1,"w") : : "a" (value), "Nd" (port)); } \ -__OUT1(s##_p,x) __OUT2(s,s1,"w") __FULL_SLOW_DOWN_IO : : "a" (value), "Nd" (port));} \ +__OUT1(s,x) __OUT2(s,s1,"w"); } \ +__OUT1(s##_p,x) __OUT2(s,s1,"w"); slow_down_io(); } #define __IN1(s) \ static inline RETURN_TYPE in##s(unsigned short port) { RETURN_TYPE _v; #define __IN2(s,s1,s2) \ -__asm__ __volatile__ ("in" #s " %" s2 "1,%" s1 "0" +__asm__ __volatile__ ("in" #s " %" s2 "1,%" s1 "0" : "=a" (_v) : "Nd" (port)) -#define __IN(s,s1,i...) \ -__IN1(s) __IN2(s,s1,"w") : "=a" (_v) : "Nd" (port) ,##i ); return _v; } \ -__IN1(s##_p) __IN2(s,s1,"w") __FULL_SLOW_DOWN_IO : "=a" (_v) : "Nd" (port) ,##i ); return _v; } \ +#define __IN(s,s1) \ +__IN1(s) __IN2(s,s1,"w"); return _v; } \ +__IN1(s##_p) __IN2(s,s1,"w"); slow_down_io(); return _v; } #define __INS(s) \ static inline void ins##s(unsigned short port, void * addr, unsigned long count) \