Hi Jerry, 2012/10/30 <r66093@xxxxxxxxxxxxx>: > From: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx> > > 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. > > Therefore, add callback function get_cd() to check whether > the card has been removed when the driver has this callback function. > > If the card is present, 1 will return, if the card is absent, 0 will return. > If the controller will not support this feature, -ENOSYS will return. In what cases is the performance affected by this? I believe this function is called only on some errors and on detect? Also, we've seen cases where the card detect GPIO cannot be trusted to tell wether the card is present or not, for instance in the corner case when an SD-card is removed very slowly... Kind regards, Johan -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
