On Wed, 26 Jan 2005 12:05:47 -0500 (EST), linux-os
<[EMAIL PROTECTED]> wrote:
> On Wed, 26 Jan 2005, Dmitry Torokhov wrote:
>
> > On Wed, 26 Jan 2005 16:43:07 +0100, Vojtech Pavlik <[EMAIL PROTECTED]>
> > wrote:
> >> On Tue, Jan 25, 2005 at 02:41:14AM -0500, Dmitry Torokhov wrote:
> >>> @@ -213,7 +217,10 @@
> >>> if (!retval)
> >>> for (i = 0; i < ((command >> 8) & 0xf); i++) {
> >>> if ((retval = i8042_wait_read())) break;
> >>> - if (i8042_read_status() & I8042_STR_AUXDATA)
> >>> + udelay(I8042_STR_DELAY);
> >>> + str = i8042_read_status();
> >> []
> >>> + udelay(I8042_DATA_DELAY);
> >>> + if (str & I8042_STR_AUXDATA)
> >>> param[i] = ~i8042_read_data();
> >>> else
> >>> param[i] = i8042_read_data();
> >>
> >> We may as well drop the negation. It's a bad way to signal the data came
> >> from the AUX port. Then we don't need the extra status read and can just
> >> proceed to read the data, since IMO we don't need to wait inbetween,
> >> even according to the IBM spec.
> >
> > Do you remember why it has been done to begin with?
> >
> > --
> > Dmitry
>
>
> The only time you need any delay at all is after you have send
...
Thank you Richard for this thorough explanation of IO access but I was
actually asking why we wanted to invert AUX data.
--
Dmitry
-
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