Re: [PATCH 00/03] i2c-i801: Add basic interrupt support

From: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
To: Ivo Manca <pinkel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Hans-cy1Wll9GaHOsTnJN9+BGXg@public.gmane.org,
	i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org,
	Goede <j.w.r.degoede-fbo2DhPpy/Q@public.gmane.org>
Subject: Re: [PATCH 00/03] i2c-i801: Add basic interrupt support
Date: Sun, 10 Aug 2008 19:05:22 +0200	[thread overview]
Message-ID: <20080810190522.76a61673@hyperion.delvare> (raw)
In-Reply-To: <488762A0.8030409-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Hi Ivo,

On Wed, 23 Jul 2008 18:56:00 +0200, Ivo Manca wrote:
> Hey All,
> 
> It's been a while since I last posted about this matter, but the patch 
> is finally there.
> 
> This patch adds basic interrupt support to the i2c-i801 bus driver. This 
> means i2c transactions can be completed without useless and pricy 
> waiting loops (the polling) and speeds things up.
> Currently only basic transactions are support. The HW PEC or i2c block 
> transactions still use polling.

Ah, really great! Thanks for working on this :)

Is there any inherent difficulty to get interrupts to work with HW PEC?
And with I2C block transactions? Or did you just not get around to
doing it?

> To write this patch, I've extensively used Mark M. Hoffman's i2c-i801 
> rewrite of the i2c-i801 driver dating back from 28 Nov 2008. This can be 
> found at http://archives.andrew.net.au/lm-sensors/msg28496.html

Yeah, Mark has been traveling a lot in time lately. Unfortunately this
also means that we can't watch this archived post yet, it'll be a few
more months before it shows up! ;)

(Seriously, archives.andrew.net.au is the old list archive and
apparently it has been discontinued, please use lists.lm-sensors.org
instead.)

> I've tested this patch extensively on a machine provided by the Hague 
> University (Thanks Hans! ;) which is ICH5 based, but it needs a lot of 
> more testing. So please be welcome to give the patch a shot.
> 
> Since I’m completely new to linux device driver development, interrupts 
> and i2c, stupid mistakes can be very well possible. Please use this 
> patch with caution and let me know whatever I did wrong :). Oh, and if 
> your PC won’t start up anymore, removing power from the PC always worked 
> for me ;p.

I've just given it a quick try on my old ICH3-M-based laptop and it
seems to work fine there. The speed improvement compared to the polling
code is very impressive.

I'm going to do more tests on 2 other machines (with ICH5 and ICH7
respectively) and will report when I'm done. A patch review will also
follow.

> All patches are made against 2.6.26-rc9

The i2c-i801 driver has changed a lot since then. Any chance you could
respin the patches against 2.6.27-rc2?

> Patch 1 implements the functionality, while patch 2 only adds the 
> alignment changes. This is done to make it easier reviewable. Patch 3 is 
> quite unrelated and only fixes some checkPatch warnings..

Thanks,
-- 
Jean Delvare

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