Re: [PATCH] mmc: dt: Add 'broken-cd' DT binding

[Chris Ball <cjb@laptop.org>]

Hi Shawn,

On Wed, Aug 22 2012, Shawn Guo wrote:
>     mmc: sdhci: Always pass clock request value zero to set_clock host op
>
>     To allow the set_clock host op to disable the SDCLK source when not
>     needed, always call the host op when the requested clock speed is
>     zero.  Do this even if host->clock already equals zero, because
>     the SDHCI driver may set that value (without calling the host op)
>     to force an update at the next (non-zero-speed) call.
>
>     Signed-off-by: Todd Poynor <toddpoynor@google.com>
>     Acked-by: Adrian Hunter <adrian.hunter@intel.com>
>     Signed-off-by: Chris Ball <cjb@laptop.org>
>
> Reverting the commit will get "controller" mode back to work.

Weird; I wonder how that's related to card detection.

I'm afraid it's ultimately a driver bug -- esdhc should be able to
handle having set_clock called with a value of 0.  It seems to have
a case in esdhc_set_clock() for 0, so I'm surprised it's not working.

What's the symptom of the failure?  Can you debug some more?

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child