From: Tom Rini <trini@ti.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 1/5] input: Use finer grain udelays while waitng for the i8042 keyboard buffer to empty
Date: Sat, 20 Oct 2012 10:42:37 -0700 [thread overview]
Message-ID: <20121020174237.GG5854@bill-the-cat> (raw)
In-Reply-To: <1350004554-18506-1-git-send-email-sjg@chromium.org>
On Thu, Oct 11, 2012 at 06:15:49PM -0700, Simon Glass wrote:
> From: Gabe Black <gabeblack@chromium.org>
>
> On x86, the i8042 keyboard controller driver frequently waits for the keyboard
> input buffer to be empty to make sure the controller has had a chance to
> process the data it was given. The way the delay loop was structured, if the
> controller hadn't cleared the corresponding status bit immediately, it would
> wait 1ms before checking again. If the keyboard responded quickly but not
> instantly, the driver would still wait a full 1ms when perhaps 1us would have
> been sufficient. Because udelay is a busy wait anyway, this change decreases
> the delay between checks to 1us.
>
> Also, this change gets rid of a hardcoded 250ms delay.
>
> On Stumpy, this saves 100-150ms during boot.
>
> Signed-off-by: Gabe Black <gabeblack@chromium.org>
> Signed-off-by: Simon Glass <sjg@chromium.org>
This, or more precisely, v2 of 1/5 and 2/5 and v1 of 3, 4 and 5/5 have
been applied to u-boot/master, thanks!
--
Tom
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prev parent reply other threads:[~2012-10-20 17:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-12 1:15 [U-Boot] [PATCH 1/5] input: Use finer grain udelays while waitng for the i8042 keyboard buffer to empty Simon Glass
2012-10-12 1:15 ` [U-Boot] [PATCH 2/5] input: Provide a board specific mechanism to decide whether to skip i8042 init Simon Glass
2012-10-12 16:05 ` Tom Rini
2012-10-13 0:03 ` Simon Glass
2012-10-12 1:15 ` [U-Boot] [PATCH 3/5] input: i8042: Provide feature to disable keyboard before booting kernel Simon Glass
2012-10-12 1:15 ` [U-Boot] [PATCH 4/5] input: Fix i8042 keyboard reset Simon Glass
2012-10-12 1:15 ` [U-Boot] [PATCH 5/5] input: Add ANSI 3.64 escape sequence generation Simon Glass
2012-10-12 3:55 ` [U-Boot] [PATCH 1/5] input: Use finer grain udelays while waitng for the i8042 keyboard buffer to empty Graeme Russ
2012-10-12 23:44 ` Simon Glass
2012-10-20 17:42 ` Tom Rini [this message]
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