[PATCH 2/3] powerpc/esdhc: add property to disable the CMD23

Kumar Gala galak at kernel.crashing.org
Wed Sep 12 22:13:41 EST 2012


On Sep 12, 2012, at 1:18 AM, Huang Changming-R66093 wrote:

> 
> 
> Best Regards
> Jerry Huang
> 
> 
>> -----Original Message-----
>> From: Chris Ball [mailto:cjb at laptop.org]
>> Sent: Wednesday, September 12, 2012 4:59 AM
>> To: Kumar Gala
>> Cc: Huang Changming-R66093; linuxppc-dev at lists.ozlabs.org list; linux-
>> mmc at vger.kernel.org; Anton Vorontsov
>> Subject: Re: [PATCH 2/3] powerpc/esdhc: add property to disable the CMD23
>> 
>> Hi,
>> 
>> On Tue, Sep 11 2012, Kumar Gala wrote:
>>> thanks for the info.  Do you know what's required on controller side
>>> to handle cards that support CMD23?
>>> 
>>> I'm trying to figure out if older controller's on FSL SoCs are missing
>>> some feature to allow CMD23 to work (vs Auto-CMD23).
>> 
>> It seems plausible that it's just not implemented on these controllers.
>> It's a little strange, since the command's been specified for so long and
>> we haven't seen any other controllers with problems.  The patch would be
>> correct if this is true.
>> 
> 
> I didn't find any description about it, but after testing on FSL silicones, I got this result:
> Some silicones support this command, and some silicones don't support it, which will cause I/O error.

Can you list out which SoCs support it and which don't.  Having this list will be useful in understanding which controller versions supported it.

- k


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