Linux Post codes during runtime, possibly OT
Quoted 5 lines
+ *
+ * Changed the slow-down I/O port from0x80to0x19.0x19is a
+ * DMA controller scratch register. [email protected] */
What about making that a config option?
default: delay with 'outb 0x80', other options could be
udelay(n); (n=1,2,3) outb 0x19
0x80 is a safe port, and IMHO changing the port on all i386 systems because it's needed for some embedded system debuggers is too dangerous.
--
Manfred
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Quoted 5 lines · Manfred Spraul
Quoted 5 lines
+ *
+ * Changed the slow-down I/O port from0x80to0x19.0x19is a
+ * DMA controller scratch register. [email protected] */
Quoted 9 lines
What about making that a config option?
default: delay with 'outb
0x80', other options could beudelay(n); (n=1,2,3) outb 0x19
0x80is a safe port, and IMHO changing the port on all i386 systems because it's needed for some embedded system debuggers is too dangerous.
Dangerous? udelay(1) on a 33 MHz system is like udelay(100). Don't get too used to 800+ MHz CPUs. There are systems, probably most in the world, that need 300 +/- nanosecond delays. This is what the port I/O does.
Cheers,
Dick Johnson
Penguin : Linux version 2.4.0 on an i686 machine (799.53 BogoMips).
"Memory is like gasoline. You use it up when you are running. Of course you get it all back when you reboot..."; Actual explanation obtained from the Micro$oft help desk.
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Quoted 14 lines · Richard B. Johnson
Quoted 11 lines · Manfred Spraul
Quoted 5 lines
+ *
+ * Changed the slow-down I/O port from0x80to0x19.0x19is a
+ * DMA controller scratch register. [email protected] */What about making that a config option?
default: delay with 'outb
0x80', other options could beudelay(n); (n=1,2,3) outb 0x19
Quoted 7 lines
Quoted 3 lines
0x80is a safe port, and IMHO changing the port on all i386 systems because it's needed for some embedded system debuggers is too dangerous.Dangerous? udelay(1) on a 33 MHz system is like udelay(100). Don't get too used to 800+ MHz CPUs. There are systems, probably most in the world, that need 300 +/- nanosecond delays. This is what the port I/O does.
In most of the cases where this delay is needed, it is a _minimum_ delay. It is usually time enough for the hardware to react to an index register being written to, etc. In most cases, a longer delay on slower machines should not hurt.
--
Brian Gerst
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Hi!
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Quoted 5 lines
+ *
+ * Changed the slow-down I/O port from0x80to0x19.0x19is a
+ * DMA controller scratch register. [email protected] */What about making that a config option?
default: delay with 'outb
0x80', other options could beudelay(n); (n=1,2,3) outb 0x19Quoted 7 lines
Quoted 3 lines
0x80is a safe port, and IMHO changing the port on all i386 systems because it's needed for some embedded system debuggers is too dangerous.Dangerous? udelay(1) on a 33 MHz system is like udelay(100). Don't get too used to 800+ MHz CPUs. There are systems, probably most in the world, that need 300 +/- nanosecond delays. This is what the port I/O does.
Quoted 4 lines
In most of the cases where this delay is needed, it is a _minimum_ delay. It is usually time enough for the hardware to react to an index register being written to, etc. In most cases, a longer delay on slower machines should not hurt.
Except getting your ne2000 slower by factor of 300.
Pavel
Signature · 6 lines
I'm [email protected]. "In my country we have almost anarchy and I don't care." Panos Katsaloulis describing me w.r.t. patents at [email protected] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] Please read the FAQ at http://www.tux.org/lkml/