According to the standard, the SWITCH command should be followed by a

SEND_STATUS command to check for errors.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Matt Fleming <matt@console-pimps.org>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: "Roberto A. Foglietta" <roberto.foglietta@gmail.com>
Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Cc: Denis Karpov <ext-denis.2.karpov@nokia.com>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: Philip Langdale <philipl@overt.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/mmc/core/mmc.c

@@ -416,13 +416,18 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		(host->caps & MMC_CAP_MMC_HIGHSPEED)) {
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 			EXT_CSD_HS_TIMING, 1);
-		if (err)
+		if (err && err != -EBADMSG)
 			goto free_card;
 
+		if (err) {
+			printk(KERN_WARNING "%s: switch to highspeed failed\n",
+			       mmc_hostname(card->host));
+			err = 0;
+		} else {
 			mmc_card_set_highspeed(card);
-
 			mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
 		}
+	}
 
 	/*
 	 * Compute bus speed.
@@ -456,11 +461,18 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				 EXT_CSD_BUS_WIDTH, ext_csd_bit);
 
-		if (err)
+		if (err && err != -EBADMSG)
 			goto free_card;
 
+		if (err) {
+			printk(KERN_WARNING "%s: switch to bus width %d "
+			       "failed\n", mmc_hostname(card->host),
+			       1 << bus_width);
+			err = 0;
+		} else {
 			mmc_set_bus_width(card->host, bus_width);
 		}
+	}
 
 	if (!oldcard)
 		host->card = card;

drivers/mmc/core/mmc_ops.c

@@ -390,6 +390,7 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value)
 {
 	int err;
 	struct mmc_command cmd;
+	u32 status;
 
 	BUG_ON(!card);
 	BUG_ON(!card->host);
@@ -407,6 +408,28 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value)
 	if (err)
 		return err;
 
+	/* Must check status to be sure of no errors */
+	do {
+		err = mmc_send_status(card, &status);
+		if (err)
+			return err;
+		if (card->host->caps & MMC_CAP_WAIT_WHILE_BUSY)
+			break;
+		if (mmc_host_is_spi(card->host))
+			break;
+	} while (R1_CURRENT_STATE(status) == 7);
+
+	if (mmc_host_is_spi(card->host)) {
+		if (status & R1_SPI_ILLEGAL_COMMAND)
+			return -EBADMSG;
+	} else {
+		if (status & 0xFDFFA000)
+			printk(KERN_WARNING "%s: unexpected status %#x after "
+			       "switch", mmc_hostname(card->host), status);
+		if (status & R1_SWITCH_ERROR)
+			return -EBADMSG;
+	}
+
 	return 0;
 }
 

include/linux/mmc/mmc.h

@@ -128,6 +128,7 @@
 #define R1_STATUS(x)            (x & 0xFFFFE000)
 #define R1_CURRENT_STATE(x)	((x & 0x00001E00) >> 9)	/* sx, b (4 bits) */
 #define R1_READY_FOR_DATA	(1 << 8)	/* sx, a */
+#define R1_SWITCH_ERROR		(1 << 7)	/* sx, c */
 #define R1_APP_CMD		(1 << 5)	/* sr, c */
 
 /*