From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: linux-os@analogic.com
Cc: Vojtech Pavlik <vojtech@suse.cz>,
linux-input@atrey.karlin.mff.cuni.cz,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org
Subject: Re: i8042 access timings
Date: Wed, 26 Jan 2005 13:30:28 -0500 [thread overview]
Message-ID: <d120d500050126103047aa6168@mail.gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.61.0501261156330.18131@chaos.analogic.com>
On Wed, 26 Jan 2005 12:05:47 -0500 (EST), linux-os
<linux-os@analogic.com> wrote:
> On Wed, 26 Jan 2005, Dmitry Torokhov wrote:
>
> > On Wed, 26 Jan 2005 16:43:07 +0100, Vojtech Pavlik <vojtech@suse.cz> 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
next prev parent reply other threads:[~2005-01-26 23:43 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-25 7:41 i8042 access timings Dmitry Torokhov
2005-01-25 10:51 ` Andries Brouwer
2005-01-25 19:17 ` Dmitry Torokhov
2005-01-25 19:25 ` Vojtech Pavlik
2005-01-25 19:41 ` Dmitry Torokhov
2005-01-25 19:46 ` Andries Brouwer
2005-01-25 20:37 ` Lee Revell
2005-01-27 15:14 ` Alan Cox
2005-01-27 16:24 ` Vojtech Pavlik
2005-01-27 16:34 ` Bill Rugolsky Jr.
2005-01-27 16:37 ` Vojtech Pavlik
2005-02-13 0:16 ` Bill Rugolsky Jr.
2005-02-13 8:22 ` Vojtech Pavlik
2005-02-13 16:17 ` Bill Rugolsky Jr.
2005-01-27 17:45 ` Andries Brouwer
2005-01-28 14:55 ` Vojtech Pavlik
2005-01-25 12:44 ` Alan Cox
2005-01-25 12:44 ` Alan Cox
2005-01-26 15:43 ` Vojtech Pavlik
2005-01-26 16:36 ` Dmitry Torokhov
2005-01-26 17:05 ` linux-os
2005-01-26 18:30 ` Dmitry Torokhov [this message]
2005-01-27 10:19 ` Vojtech Pavlik
[not found] <200501260040.46288.sebekpi@poczta.onet.pl>
2005-01-27 6:23 ` Jaco Kroon
2005-01-27 10:25 ` Vojtech Pavlik
2005-01-27 11:12 ` Sebastian Piechocki
2005-01-27 11:31 ` Vojtech Pavlik
2005-01-27 17:33 ` Jaco Kroon
2005-01-27 18:09 ` Linus Torvalds
2005-01-27 20:29 ` Andries Brouwer
2005-01-27 20:41 ` Dmitry Torokhov
2005-01-27 23:11 ` Andries Brouwer
2005-01-28 13:17 ` Vojtech Pavlik
2005-01-28 14:20 ` Jaco Kroon
2005-01-28 18:39 ` Vojtech Pavlik
2005-01-29 19:59 ` Jaco Kroon
2005-01-29 23:21 ` Dmitry Torokhov
2005-01-29 20:02 ` Randy.Dunlap
2005-01-27 20:51 ` Jaco Kroon
2005-01-27 21:17 ` Linus Torvalds
2005-01-27 22:12 ` Jaco Kroon
2005-01-27 22:36 ` Linus Torvalds
2005-01-27 23:40 ` Dmitry Torokhov
2005-01-28 5:52 ` Jaco Kroon
2005-02-04 19:54 ` Bukie Mabayoje
2005-01-28 11:04 ` Vojtech Pavlik
2005-01-27 20:23 ` Andries Brouwer
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