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

Wolfram Sang
2011-02-15T10:16:32Z

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?

Regards,

Wolfram

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