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Merge master.kernel.org:/home/rmk/linux-2.6-mmc

Linus Torvalds 19 years ago
parent
commit
9d149c27eb
1 changed files with 9 additions and 1 deletions
  1. 9 1
      drivers/mmc/mmc.c

+ 9 - 1
drivers/mmc/mmc.c

@@ -679,7 +679,15 @@ static void mmc_idle_cards(struct mmc_host *host)
 }
 
 /*
- * Apply power to the MMC stack.
+ * Apply power to the MMC stack.  This is a two-stage process.
+ * First, we enable power to the card without the clock running.
+ * We then wait a bit for the power to stabilise.  Finally,
+ * enable the bus drivers and clock to the card.
+ *
+ * We must _NOT_ enable the clock prior to power stablising.
+ *
+ * If a host does all the power sequencing itself, ignore the
+ * initial MMC_POWER_UP stage.
  */
 static void mmc_power_up(struct mmc_host *host)
 {