Re: [PATCH] mmc: disable tuning when checking card presence

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

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Hi Adrian, Ulf, everyone,

> With the code above, if the host controller knows the card has been
> removed, it can return -ENOMEDIUM from ->execute_tuning() to suppress
> the message.

On second thought, I like the idea with -ENOMEDIUM. Because tuning can
still fail for reasons other than a removed card and we want to see an
error message then.

So, I checked when/how to return -ENOMEDIUM for the SDHI driver but this
lead me to more questions. The few driver which return this error code
all follow a similar pattern:

xxx_request()
{
	if (host->get_cd == 1)
		submit_mrq
	else
		cmd->error = -ENOMEDIUM
		mmc_request_done()
}

So, my first question would be if we can't apply this pattern in the
core before calling the .request callback? A lot of drivers are not
implementing this pattern although it seems useful. Is it required?
Recommended? Nice to have? However, I could imagine an answer for moving
it into the core is "no, that should be checked atomically"? E.g. sdhci
does it, but atmel-mci and s3cmci do not. If I just look at moving the
card detection call into the core, I don't really see the reason for
atomic. Am I missing something?

All the best,

   Wolfram


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