From mboxrd@z Thu Jan  1 00:00:00 1970
From: tim.nordell@logicpd.com (Tim Nordell)
Date: Thu, 21 Oct 2010 14:10:58 -0500
Subject: [PATCH] ARM: OMAP: Modified omap_mux_init_signal() to take in
	const char *
In-Reply-To: <1287687041-22377-1-git-send-email-tim.nordell@logicpd.com>
References: <1287687041-22377-1-git-send-email-tim.nordell@logicpd.com>
Message-ID: <4CC09042.3000201@logicpd.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

 On 10/21/10 13:50, Tim Nordell wrote:
> If one does the following line twice with the old code:
>
> omap_mux_init_signal("uart3_rts_sd.gpio_164", OMAP_PIN_INPUT);
> omap_mux_init_signal("uart3_rts_sd.gpio_164", OMAP_PIN_INPUT);
>
> the compiler optimizes the two const strings into one string
> internally in the compiler.  The old code would modify the string
> by inserting a NULL effectively making the second call become:
>
> omap_mux_init_signal("uart3_rts_sd", OMAP_PIN_INPUT);
>
> Since the code changes _all_ uart3_rts_sd signals over to this,
> it'll cause unknown behavior, as well as making it more
> difficult to track down the reason since the string
> "uart3_rts_sd" by itself may not actually exist in your
> normal mux initialization sequence.
>

Gah.  I just realized there was a patch in the linux-omap tree to do the
same thing.

http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=commitdiff;h=5a3b2f7a5a79082dd3a5f2294cbd85fc3b173d98;hp=7ad0e386d46e9edff64705ab25337ad9130baf63

It looks like by inspection that there could be a couple of things wrong
with that patch however.  Namely, on the comparison of muxname to
m0_entry, if they have the same string up to mode0_len, such as
"dss_data1" and "dss_data12" it'd match there prematurely as it'd stop
comparing.  Also, a minor display issue on the printk of the new muxname.

- Tim