TF卡经常不能识别

CONFIG_MMC_PARANOID_SD_INIT

static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,

static void mmc_sd_detect(struct mmc_host *host)

int mmc_attach_sd(struct mmc_host *host, u32 ocr)

static const struct mmc_bus_ops mmc_sd_ops = {

        .remove = mmc_sd_remove,

        .detect = mmc_sd_detect,

void mmc_rescan(struct work_struct *work)

INIT_DELAYED_WORK(&host->detect, mmc_rescan);

struct mmc_host *mmc_alloc_host(int extra, struct device *dev)

struct sdhci_host *sdhci_alloc_host(struct device *dev,

        size_t priv_size)

static int __devinit sdhci_s3c_probe(struct platform_device *pdev)

struct s3c_sdhci_platdata *pdata = pdev->dev.platform_data;

struct platform_device s3c_device_hsmmc2 = {

        .name           = "s3c-sdhci",

        .id             = 2,

mmc_sd_detect(mmc2): Unable to re-detect card (-84)

void mmc_detect_change(struct mmc_host *host, unsigned long delay)

static void sdhci_tasklet_card(unsigned long param)

void mmc_start_host(struct mmc_host *host)

{

        mmc_power_off(host);

        mmc_detect_change(host, 0);

}

int mmc_add_host(struct mmc_host *host)

int sdhci_add_host(struct sdhci_host *host)

解决方法：

打开选项：CONFIG_MMC_PARANOID_SD_INIT，在插入SD卡时重试几次。

drivers/mmc/core/sd.c

int mmc_attach_sd(struct mmc_host *host, u32 ocr)

{

#ifdef CONFIG_MMC_PARANOID_SD_INIT

        retries = 5;

        while (retries) {

                err = mmc_sd_init_card(host, host->ocr, NULL);

                if (err) {

                        retries--;

                        msleep(50); //jeff.

                        continue;

                }

                break;

        }

.....

}

drivers/mmc/host/sdhci.c

static void sdhci_tasklet_card(unsigned long param)

{

.....

        //jeff. mmc_detect_change(host->mmc, msecs_to_jiffies(200));

        mmc_detect_change(host->mmc, msecs_to_jiffies(500));

}

做这样的修改后，正常的插拔tf卡可以识别，但有一种情况是不行的，那就是：

快速将tf卡插到底，不弹起，过几秒后再松，这样不会再有一个识别的过程，

这是由于卡座在插到底时卡座与tf卡没有接触。