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-rw-r--r--drivers/mmc/core/sd.c24
1 files changed, 20 insertions, 4 deletions
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 5afac2081185..41bfb5dfe6ff 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -15,6 +15,7 @@
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/mmc.h>
+#include <linux/mmc/sd.h>
#include "core.h"
#include "sysfs.h"
@@ -192,6 +193,16 @@ static int mmc_read_switch(struct mmc_card *card)
int err;
u8 *status;
+ if (card->scr.sda_vsn < SCR_SPEC_VER_1)
+ return MMC_ERR_NONE;
+
+ if (!(card->csd.cmdclass & CCC_SWITCH)) {
+ printk(KERN_WARNING "%s: card lacks mandatory switch "
+ "function, performance might suffer.\n",
+ mmc_hostname(card->host));
+ return MMC_ERR_NONE;
+ }
+
err = MMC_ERR_FAILED;
status = kmalloc(64, GFP_KERNEL);
@@ -204,10 +215,9 @@ static int mmc_read_switch(struct mmc_card *card)
err = mmc_sd_switch(card, 0, 0, 1, status);
if (err != MMC_ERR_NONE) {
- /*
- * Card not supporting high-speed will ignore the
- * command.
- */
+ printk(KERN_WARNING "%s: problem reading switch "
+ "capabilities, performance might suffer.\n",
+ mmc_hostname(card->host));
err = MMC_ERR_NONE;
goto out;
}
@@ -229,6 +239,12 @@ static int mmc_switch_hs(struct mmc_card *card)
int err;
u8 *status;
+ if (card->scr.sda_vsn < SCR_SPEC_VER_1)
+ return MMC_ERR_NONE;
+
+ if (!(card->csd.cmdclass & CCC_SWITCH))
+ return MMC_ERR_NONE;
+
if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
return MMC_ERR_NONE;