Re: [PATCH 2/4] MMC/SD: Add callback function to detect card

[Adrian Hunter <adrian.hunter@intel.com>]

On 05/12/11 11:23, r66093@freescale.com wrote:
> From: Jerry Huang <Chang-Ming.Huang@freescale.com>
> 
> In order to check whether the card has been removed, the function
> mmc_send_status() will send command CMD13 to card and ask the card
> to send its status register to sdhc driver, which will generate
> many interrupts repeatedly and make the system performance bad.

That should not be true.  sdhci.c will not send a command to the
card if the card is not present i.e. see this excerpt from
sdhci_request():


	/* If polling, assume that the card is always present. */
	if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)
		present = true;
	else
		present = sdhci_readl(host, SDHCI_PRESENT_STATE) &
				SDHCI_CARD_PRESENT;

	if (!present || host->flags & SDHCI_DEVICE_DEAD) {
		host->mrq->cmd->error = -ENOMEDIUM;
		tasklet_schedule(&host->finish_tasklet);