Index: linux-2.6.39.4/drivers/mmc/core/core.c
===================================================================
--- linux-2.6.39.4.orig/drivers/mmc/core/core.c	2011-08-03 14:43:28.000000000 -0500
+++ linux-2.6.39.4/drivers/mmc/core/core.c	2012-09-12 10:45:57.246686939 -0500
@@ -46,7 +46,10 @@
  * So we allow it it to be disabled.
  */
 int use_spi_crc = 1;
+/* MTPCIE: default max clock to 13MHz */
+int max_clock = 13000000;
 module_param(use_spi_crc, bool, 0);
+module_param(max_clock, int, 0);
 
 /*
  * We normally treat cards as removed during suspend if they are not
@@ -628,6 +631,12 @@
 
 	if (ios->clock > 0)
 		mmc_set_ungated(host);
+
+	if (max_clock > 0 && ios->clock > max_clock) {
+		ios->clock = max_clock;
+		printk("mmc: forcing clock to %u\n", ios->clock);
+	}
+
 	host->ops->set_ios(host, ios);
 }