RE: [PATCH 02/12] mmc: sd: add support for signal voltage switch procedure

Nath, Arindam
2011-02-16T07:55:26Z

Hi Wolfram,

> -----Original Message-----
> From: Wolfram Sang [mailto:w.sang@pengutronix.de]
> Sent: Tuesday, February 15, 2011 3:46 PM
> To: Nath, Arindam
> Cc: cjb@laptop.org; linux-mmc@vger.kernel.org; Su, Henry; Lu, Aaron;
> anath.amd@gmail.com
> Subject: Re: [PATCH 02/12] mmc: sd: add support for signal voltage
> switch procedure
>
> On Tue, Feb 15, 2011 at 03:05:00PM +0530, Arindam Nath wrote:
>
> > Host Controller v3.00 adds another Capabilities register. We can
> > directly read this register without any version checking since the
> > new register bits will be considred as reserved in older controllers,
> > and will be read as 0.
>
> I so much wish you were right, but reality is different :(
>
> The i.MX35-processor, for example, has a custom watermark-register
> there. I
> could fix this by intercepting the read using io-accessors, but to
> minimize
> potential regressions on older controllers in general, I'd say the
> check for v3
> might be justified?

Thanks for the suggestion. I will add the changes in V2 of the patchset.

Regards,
Arindam