- Original Message -
From: "Richard B. Johnson" <[EMAIL PROTECTED]>
To: "mirabilos" <[EMAIL PROTECTED]>
Cc: "Linux-Kernel ML" <[EMAIL PROTECTED]>; "Mark H. Wood" <[EMAIL PROTECTED]>
Sent: Tuesday, January 30, 2001 6:36 PM
On Tue, 30 Jan 2001, mirabilos wrote:
> [...]
> > >
> > > Now, we've found that small delays are reasonably well generated with
> > > an "outb" to 0x80. So, indeed changing that to something else is going
> > > to be tricky.
> >
> > So how bad would it be to give these people a place to leave
[...]
> >
> > Now, we've found that small delays are reasonably well generated with
> > an "outb" to 0x80. So, indeed changing that to something else is going
> > to be tricky.
>
> So how bad would it be to give these people a place to leave the value
> that they want to have displayed, and hav
On Tue, 30 Jan 2001, Mark H. Wood wrote:
> On Sat, 27 Jan 2001, Rogier Wolff wrote:
> [snip]
> > I may have missed too much of the discussion, but I thought that the
> > idea was that some people noted that their POST-code-cards don't
> > really work all that well when Linux is running because Li
On Sat, 27 Jan 2001, Rogier Wolff wrote:
[snip]
> I may have missed too much of the discussion, but I thought that the
> idea was that some people noted that their POST-code-cards don't
> really work all that well when Linux is running because Linux keeps on
> sending garbage to port 0x80.
>
> Y
Pavel Machek wrote:
>> >
> > And you're still overwriting the POST value written by the BIOS.
>
> So save value from bios at initial boot ;-).
> Pavel
Write-only register.
-hpa
--
<[EMAIL PROTECTED]> at work, <[EMAIL PROT
On Sun, 28 Jan 2001, Pavel Machek wrote:
> Hi!
>
> > > Ok. I've thought about it some more, but I don't care enough about
> > > this issue to do the painstaking legwork: I don't have one of those
> > > POST-code indicators on port 0x80.
> > >
> > > I've made the "pause" in outb_p just a few (*)
Hi!
> > > > It output garbage to the 80h port in order to enforce I/O delays.
> > > > It's one of the safe ports to issue outs to.
>
> > > Yes, because it is reserved for POST codes. You can get "POST
> > > debugging cards" that simply have a BIN -> 7segement encoder and two 7
> > > segment disp
Hi!
> > Ok. I've thought about it some more, but I don't care enough about
> > this issue to do the painstaking legwork: I don't have one of those
> > POST-code indicators on port 0x80.
> >
> > I've made the "pause" in outb_p just a few (*) ns slower, because it
> > now loads a variable before o
> Actually, what you need to do is change it and then try it on something
> like 300 different systems. Since noone has direct access to that kind
> of system, you have to get people to help you out trying it.
>
> A better idea might be to find out what port, if any, Windows uses. If
> Windows
H. Peter Anvin wrote:
> It is; you'd have to specify "eax" as a clobber value, and that is
> undesirable.
For outb_p, EAX is used, usually for the last time, in the preceding
"out" instruction so clobbering it is not a big deal.
For inb_p, you first have to copy EAX to another register before
ou
H. Peter Anvin wrote:
> Rogier Wolff wrote:
> >
> > Ok. I've thought about it some more, but I don't care enough about
> > this issue to do the painstaking legwork: I don't have one of those
> > POST-code indicators on port 0x80.
> >
> > I've made the "pause" in outb_p just a few (*) ns slower,
Rogier Wolff wrote:
>
> Ok. I've thought about it some more, but I don't care enough about
> this issue to do the painstaking legwork: I don't have one of those
> POST-code indicators on port 0x80.
>
> I've made the "pause" in outb_p just a few (*) ns slower, because it
> now loads a variable be
H. Peter Anvin wrote:
> > All that I can think of right now is:
> > - Find a register that can be written without side effects in
> > "standard" hardware like a keyboard controller, or interrupt
> >controller. Especially good are ones that already require us to keep
> >a shadow value. W
Rogier Wolff wrote:
>
> You seem to state that if you want POST codes, you should find a
> different port, modify the code, test the hell out of it, and then
> submit the patch.
>
> That is NOT the right way to go about this: Port 0x80 is RESERVED for
> POST usage, that's why it's always free. I
H. Peter Anvin wrote:
> Rogier Wolff wrote:
> > H. Peter Anvin wrote:
> > > It output garbage to the 80h port in order to enforce I/O delays.
> > > It's one of the safe ports to issue outs to.
> > Yes, because it is reserved for POST codes. You can get "POST
> > debugging cards" that simply have
Rogier Wolff wrote:
>
> H. Peter Anvin wrote:
> > Followup to: <[EMAIL PROTECTED]>
> > By author:"Ian S. Nelson" <[EMAIL PROTECTED]>
> > In newsgroup: linux.dev.kernel
> > >
> > > I'm curious. Why does Linux make that friendly 98/9a/88 looking
> > > postcode pattern when it's running? DOS
Hi!
> > > > + *
> > > > + * Changed the slow-down I/O port from 0x80 to 0x19. 0x19 is a
> > > > + * DMA controller scratch register. [EMAIL PROTECTED]
> > > >*/
> > > >
> > > What about making that a config option?
> > >
> > > default: delay with 'outb 0x80', other options could be
> > >
H. Peter Anvin wrote:
> Followup to: <[EMAIL PROTECTED]>
> By author:"Ian S. Nelson" <[EMAIL PROTECTED]>
> In newsgroup: linux.dev.kernel
> >
> > I'm curious. Why does Linux make that friendly 98/9a/88 looking
> > postcode pattern when it's running? DOS and DOS95 don't do that.
> >
> > I'm
On Fri, Jan 26, 2001 at 08:19:58AM -0800, H. Peter Anvin wrote:
>
> A better idea might be to find out what port, if any, Windows uses. If
> Windows does it, it is usually safe.
>
Windows NT 4 Service Pack 6 doesn't use any delay however
READ/WRITE_PORT_* are implemented as indirect function c
"Richard B. Johnson" wrote:
>
> On Fri, 26 Jan 2001, Manfred Spraul wrote:
>
> > > + *
> > > + * Changed the slow-down I/O port from 0x80 to 0x19. 0x19 is a
> > > + * DMA controller scratch register. [EMAIL PROTECTED]
> > >*/
> > >
> > What about making that a config option?
> >
> > default:
Richard B. Johnson wrote:
> Slowing down I/O is absolutely necessary any time you set an index
> register or a page register. For instance, to access the CMOS chip,
> you write an index value out port 0x70, then you read or write from
> port 0x71. Modern CPUs can execute instructions MUCH faster t
"Richard B. Johnson" wrote:
>
> I will change the port on my machines and run them for a week. I
> don't have any DEC Rainbows or other such. Yes, I know Linux will
> not run on a '286.
>
> Since 0x19 is a hardware register in a DMA controller, specifically
> called a "scratch" register, it is u
On Fri, 26 Jan 2001, Manfred Spraul wrote:
> > + *
> > + * Changed the slow-down I/O port from 0x80 to 0x19. 0x19 is a
> > + * DMA controller scratch register. [EMAIL PROTECTED]
> >*/
> >
> What about making that a config option?
>
> default: delay with 'outb 0x80', other options could
On Fri, 26 Jan 2001, Jamie Lokier wrote:
> Mark Hahn wrote:
> > > #ifdef SLOW_IO_BY_JUMPING
> > > #define __SLOW_DOWN_IO "\njmp 1f\n1:\tjmp 1f\n1:"
> > > #else
> > > -#define __SLOW_DOWN_IO "\noutb %%al,$0x80"
> > > +#define __SLOW_DOWN_IO "\noutb %%al,$0x19"
> >
> > this is nutty: why can't
> + *
> + * Changed the slow-down I/O port from 0x80 to 0x19. 0x19 is 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
Mark Hahn wrote:
> > #ifdef SLOW_IO_BY_JUMPING
> > #define __SLOW_DOWN_IO "\njmp 1f\n1:\tjmp 1f\n1:"
> > #else
> > -#define __SLOW_DOWN_IO "\noutb %%al,$0x80"
> > +#define __SLOW_DOWN_IO "\noutb %%al,$0x19"
>
> this is nutty: why can't udelay be used here? empirical measurements
> in the thre
> #ifdef SLOW_IO_BY_JUMPING
> #define __SLOW_DOWN_IO "\njmp 1f\n1:\tjmp 1f\n1:"
> #else
> -#define __SLOW_DOWN_IO "\noutb %%al,$0x80"
> +#define __SLOW_DOWN_IO "\noutb %%al,$0x19"
this is nutty: why can't udelay be used here? empirical measurements
in the thread show the delay is O(2us).
-
T
On Fri, 26 Jan 2001, Petr Vandrovec wrote:
> On 26 Jan 01 at 8:58, Richard B. Johnson wrote:
> > On Thu, 25 Jan 2001, H. Peter Anvin wrote:
> > > > You could use the DMA scratch register at 0x19. I'm sure Linux doesn't
> > > > "save" stuff there when setting up the DMA controller.
> > > >
> > I
On 26 Jan 01 at 8:58, Richard B. Johnson wrote:
> On Thu, 25 Jan 2001, H. Peter Anvin wrote:
> > > You could use the DMA scratch register at 0x19. I'm sure Linux doesn't
> > > "save" stuff there when setting up the DMA controller.
> > >
> I will change the port on my machines and run them for a w
On Thu, 25 Jan 2001, H. Peter Anvin wrote:
> "Richard B. Johnson" wrote:
> >
> > On Thu, 25 Jan 2001, H. Peter Anvin wrote:
> >
> > > Matthew Dharm wrote:
> > > >
> > > > It occurs to me that it might be a good idea to pick a different port for
> > > > these things. I know a lot of people who
"Richard B. Johnson" wrote:
>
> On Thu, 25 Jan 2001, H. Peter Anvin wrote:
>
> > Matthew Dharm wrote:
> > >
> > > It occurs to me that it might be a good idea to pick a different port for
> > > these things. I know a lot of people who want to use port 80h for
> > > debugging data, especially in
On Thu, 25 Jan 2001, H. Peter Anvin wrote:
> Matthew Dharm wrote:
> >
> > It occurs to me that it might be a good idea to pick a different port for
> > these things. I know a lot of people who want to use port 80h for
> > debugging data, especially in embedded x86 systems.
> >
>
> Find a safe
Matthew Dharm wrote:
>
> Isn't that always the way in the Open Source world? :)
>
> Seriously, tho... does anyone have some list of who is using what ports?
> At least, in general?
>
There is one included in Ralf Brown's Interrupt List. No list you're
going to find is going to be complete, th
Isn't that always the way in the Open Source world? :)
Seriously, tho... does anyone have some list of who is using what ports?
At least, in general?
Matt
On Thu, Jan 25, 2001 at 02:32:41PM -0800, H. Peter Anvin wrote:
> Matthew Dharm wrote:
> >
> > It occurs to me that it might be a good idea
Matthew Dharm wrote:
>
> It occurs to me that it might be a good idea to pick a different port for
> these things. I know a lot of people who want to use port 80h for
> debugging data, especially in embedded x86 systems.
>
Find a safe port, make sure it is tested the hell out of, and we'll
con
It occurs to me that it might be a good idea to pick a different port for
these things. I know a lot of people who want to use port 80h for
debugging data, especially in embedded x86 systems.
Matt
On Thu, Jan 25, 2001 at 02:26:36PM -0800, H. Peter Anvin wrote:
> Followup to: <[EMAIL PROTECTED]
Followup to: <[EMAIL PROTECTED]>
By author:"Ian S. Nelson" <[EMAIL PROTECTED]>
In newsgroup: linux.dev.kernel
>
> I'm curious. Why does Linux make that friendly 98/9a/88 looking
> postcode pattern when it's running? DOS and DOS95 don't do that.
>
> I'm begining to feel like I can tell the
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