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From: Michael Lawnick <ml.lawnick-Mmb7MZpHnFY@public.gmane.org>
To: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
Cc: Esben Haabendal
	<esbenhaabendal-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Esben Haabendal
	<eha-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linuxppc-dev-mnsaURCQ41sdnm+yROfE0A@public.gmane.org
Subject: Re: [PATCH v2] i2c-mpc: generate START condition after STOP caused by read i2c_msg
Date: Thu, 03 Dec 2009 16:09:57 +0100	[thread overview]
Message-ID: <4B17D4C5.3070100@gmx.de> (raw)
In-Reply-To: <20090526213351.GG23114-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>

Ben Dooks said the following:
> On Tue, May 26, 2009 at 01:30:21PM +0200, Esben Haabendal wrote:
>> On Tue, May 19, 2009 at 7:22 AM, Esben Haabendal <eha-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org> wrote:
>> > This fixes MAL (arbitration lost) bug caused by illegal use of
>> > RSTA (repeated START) after STOP condition generated after last byte
>> > of reads. With this patch, it is possible to do an i2c_transfer() with
>> > additional i2c_msg's following the I2C_M_RD messages.
>> >
>> > It still needs to be resolved if it is possible to fix this issue
>> > by removing the STOP condition after reads in a robust way.
>> >
>> > Signed-off-by: Esben Haabendal <eha-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org>
>> > ---
>> > ?drivers/i2c/busses/i2c-mpc.c | ? ?9 +++++++--
>> > ?1 files changed, 7 insertions(+), 2 deletions(-)
>> 
>> Any blockers to get this accepted?
> 
> It would be nice to get an ack from someone who can actually test
> the driver before getting this merged.
>  
What is the state of this patch?
Shouldn't we attack the problem on a more general way by inventing a
Flag I2C_M_RESTART (or better I2C_M_NO_RESTART for backward compatibility)?
This way the client driver is able to decide what it needs. If we do the
choice within adapter, chance is about 50% to be wrong.

Just my 2 Cents.

-- 
Michael

WARNING: multiple messages have this Message-ID (diff)
From: Michael Lawnick <ml.lawnick@gmx.de>
To: Ben Dooks <ben-linux@fluff.org>
Cc: linuxppc-dev@ozlabs.org, Esben Haabendal <eha@doredevelopment.dk>,
	Esben Haabendal <esbenhaabendal@gmail.com>,
	linux-i2c@vger.kernel.org
Subject: Re: [PATCH v2] i2c-mpc: generate START condition after STOP caused by read i2c_msg
Date: Thu, 03 Dec 2009 16:09:57 +0100	[thread overview]
Message-ID: <4B17D4C5.3070100@gmx.de> (raw)
In-Reply-To: <20090526213351.GG23114@fluff.org.uk>

Ben Dooks said the following:
> On Tue, May 26, 2009 at 01:30:21PM +0200, Esben Haabendal wrote:
>> On Tue, May 19, 2009 at 7:22 AM, Esben Haabendal <eha@doredevelopment.dk> wrote:
>> > This fixes MAL (arbitration lost) bug caused by illegal use of
>> > RSTA (repeated START) after STOP condition generated after last byte
>> > of reads. With this patch, it is possible to do an i2c_transfer() with
>> > additional i2c_msg's following the I2C_M_RD messages.
>> >
>> > It still needs to be resolved if it is possible to fix this issue
>> > by removing the STOP condition after reads in a robust way.
>> >
>> > Signed-off-by: Esben Haabendal <eha@doredevelopment.dk>
>> > ---
>> > ?drivers/i2c/busses/i2c-mpc.c | ? ?9 +++++++--
>> > ?1 files changed, 7 insertions(+), 2 deletions(-)
>> 
>> Any blockers to get this accepted?
> 
> It would be nice to get an ack from someone who can actually test
> the driver before getting this merged.
>  
What is the state of this patch?
Shouldn't we attack the problem on a more general way by inventing a
Flag I2C_M_RESTART (or better I2C_M_NO_RESTART for backward compatibility)?
This way the client driver is able to decide what it needs. If we do the
choice within adapter, chance is about 50% to be wrong.

Just my 2 Cents.

-- 
Michael

  parent reply	other threads:[~2009-12-03 15:09 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-19  5:22 [PATCH v2] i2c-mpc: generate START condition after STOP caused by read i2c_msg Esben Haabendal
2009-05-19  5:22 ` Esben Haabendal
2009-05-26 11:30 ` Esben Haabendal
2009-05-26 11:30   ` Esben Haabendal
     [not found]   ` <d2b9ea600905260430i72290901p9266de4cade049c1-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-05-26 21:33     ` Ben Dooks
2009-05-26 21:33       ` Ben Dooks
     [not found]       ` <20090526213351.GG23114-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>
2009-05-28 17:17         ` Wolfram Sang
2009-05-28 17:17           ` Wolfram Sang
     [not found]           ` <20090528171726.GE3112-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2009-05-28 18:43             ` Joakim Tjernlund
2009-05-28 18:43               ` Joakim Tjernlund
2009-05-28 20:10           ` Esben Haabendal
     [not found]             ` <d2b9ea600905281310p16f47ed0i454e25bf256d3010-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-05-28 20:34               ` Peter Korsgaard
2009-05-28 20:34                 ` Peter Korsgaard
     [not found]                 ` <87ws8155md.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org>
2009-05-28 20:41                   ` Esben Haabendal
2009-05-28 20:41                     ` Esben Haabendal
     [not found]                     ` <d2b9ea600905281341s24efa4e3l6277a8aa5dec5bd-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-05-28 21:08                       ` Peter Korsgaard
2009-05-28 21:08                         ` Peter Korsgaard
     [not found]                         ` <87octd5415.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org>
2009-05-28 21:22                           ` Esben Haabendal
2009-05-28 21:22                             ` Esben Haabendal
2009-12-03 15:09         ` Michael Lawnick [this message]
2009-12-03 15:09           ` Michael Lawnick
     [not found]           ` <4B17D4C5.3070100-Mmb7MZpHnFY@public.gmane.org>
2009-12-03 15:29             ` Ben Dooks
2009-12-03 15:29               ` Ben Dooks
     [not found]               ` <20091203152916.GC23152-SMNkleLxa3Z6Wcw2j4pizdi2O/JbrIOy@public.gmane.org>
2009-12-03 15:49                 ` Joakim Tjernlund
2009-12-03 15:49                   ` Joakim Tjernlund
2009-12-04  6:58                 ` Michael Lawnick
2009-12-04  6:58                   ` Michael Lawnick
2009-12-03 15:42           ` Joakim Tjernlund
2009-05-28 19:31     ` Grant Likely
2009-05-28 19:31       ` Grant Likely
     [not found]       ` <fa686aa40905281231o26c74a13v250bcedbd066e77b-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-05-28 20:15         ` Esben Haabendal
2009-05-28 20:15           ` Esben Haabendal
2009-06-02 22:25           ` Ben Dooks
2009-06-02 23:12 ` Grant Likely
2009-06-02 23:12   ` Grant Likely
2009-06-03  6:01   ` Grant Likely
2009-06-03  6:01     ` Grant Likely
     [not found] ` <4A124202.4010201-SIcX2qgNSybd/EuGEV170n9LOBIZ5rWg@public.gmane.org>
2009-06-14 13:16   ` Ben Dooks
2009-06-14 13:16     ` Ben Dooks
     [not found]     ` <20090614131605.GK20446-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>
2009-06-14 14:04       ` Esben Haabendal
2009-06-14 14:04         ` Esben Haabendal

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