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Message-ID: <20071214131502.GA14359@elte.hu>
Date: Fri, 14 Dec 2007 14:15:03 +0100
From: Ingo Molnar <mingo@...e.hu>
To: "David P. Reed" <dpreed@...d.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
Rene Herman <rene.herman@...access.nl>,
Pavel Machek <pavel@....cz>
Subject: Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80
on some AMD64x2 laptops, etc.
* David P. Reed <dpreed@...d.com> wrote:
> Replace use of outb to "unused" diagnostic port 0x80 for time delay
> with udelay based time delay on x86_64 architecture machines. Fix for
> bugs 9511 and 6307 in bugzilla, plus bugs reported in
> bugzilla.redhat.com.
>
> Derived from suggestion (that didn't compile) by Pavel Machek, and
> tested, also based on measurements of typical timings of out's
> collated by Rene Herman from many in the community.
>
> This patch fixes a number of bugs known to cause problems on HP
> Pavilion dv9000z and dv6000z laptops - in the form of solid freezes
> when hwclock is used to show or set the time. Also, it potentially
> improves bus utilization on SMP machines, by using a waiting process
> that doesn't tie up the ISA/LPC bus for 1 or 2 microseconds.
>
> i386 family fixes (completely parallel) were not included, considering
> that such machines might involve more risk of problems on legacy
> machines.
wow, cool fix! (I remember that there were other systems as well that
are affected by port 0x80 muckery - i thought we had removed port 0x80
accesses long ago.)
how about the simpler fix below, as a first-level approach? We can then
remove the _p in/out sequences after this.
this is also something for v2.6.24 merging.
Ingo
----------------------------->
Subject: x86: fix in/out_p delays
From: Ingo Molnar <mingo@...e.hu>
Debugged by David P. Reed <dpreed@...d.com>.
Do not use port 0x80, it can cause crashes, see:
http://bugzilla.kernel.org/show_bug.cgi?id=6307
http://bugzilla.kernel.org/show_bug.cgi?id=9511
instead of just removing _p postfixes en masse, lets just first
remove the 0x80 port usage, then remove any unnecessary _p io ops
gradually. It's more debuggable this way.
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
arch/x86/boot/compressed/misc_32.c | 8 ++++----
arch/x86/boot/compressed/misc_64.c | 8 ++++----
arch/x86/kernel/quirks.c | 9 +++++++++
include/asm-x86/io_32.h | 5 +----
include/asm-x86/io_64.h | 5 +----
5 files changed, 19 insertions(+), 16 deletions(-)
Index: linux-x86.q/arch/x86/boot/compressed/misc_32.c
===================================================================
--- linux-x86.q.orig/arch/x86/boot/compressed/misc_32.c
+++ linux-x86.q/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)
Index: linux-x86.q/arch/x86/boot/compressed/misc_64.c
===================================================================
--- linux-x86.q.orig/arch/x86/boot/compressed/misc_64.c
+++ linux-x86.q/arch/x86/boot/compressed/misc_64.c
@@ -275,10 +275,10 @@ 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)
Index: linux-x86.q/arch/x86/kernel/quirks.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/quirks.c
+++ linux-x86.q/arch/x86/kernel/quirks.c
@@ -6,6 +6,15 @@
#include <asm/hpet.h>
+/*
+ * Some legacy devices need delays for IN/OUT sequences. Most are
+ * probably not needed but it's the safest to just do this short delay:
+ */
+void native_io_delay(void)
+{
+ udelay(1);
+}
+
#if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
static void __devinit quirk_intel_irqbalance(struct pci_dev *dev)
Index: linux-x86.q/include/asm-x86/io_32.h
===================================================================
--- linux-x86.q.orig/include/asm-x86/io_32.h
+++ linux-x86.q/include/asm-x86/io_32.h
@@ -250,10 +250,7 @@ static inline void flush_write_buffers(v
#endif /* __KERNEL__ */
-static inline void native_io_delay(void)
-{
- asm volatile("outb %%al,$0x80" : : : "memory");
-}
+extern void native_io_delay(void);
#if defined(CONFIG_PARAVIRT)
#include <asm/paravirt.h>
Index: linux-x86.q/include/asm-x86/io_64.h
===================================================================
--- linux-x86.q.orig/include/asm-x86/io_64.h
+++ linux-x86.q/include/asm-x86/io_64.h
@@ -35,10 +35,7 @@
* - Arnaldo Carvalho de Melo <acme@...ectiva.com.br>
*/
-static inline void native_io_delay(void)
-{
- asm volatile("outb %%al,$0x80" : : : "memory");
-}
+extern void native_io_delay(void);
#if defined(CONFIG_PARAVIRT)
#include <asm/paravirt.h>
--
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