mvsdio: ignore high speed timing requests from the core

Empirical evidences show that this is causing far more problems than it
solves when this mode is enabled in the host hardware.  Amongst those
cards that are known to be non functional when this bit is set are:

	A-Data "Speedy" 2GB SD card
	Kodak 512MB SD card
	Ativa 1GB MicroSD card
	Marvell 8688 (WIFI/Bluetooth) SDIO card

Since those cards do work on other host controllers which do honnor the
hs timing, the issue must be with this particular host hardware.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/mmc/host/mvsdio.c b/drivers/mmc/host/mvsdio.c
index 1783043a26af..9d3cfa9909c9 100644
--- a/drivers/mmc/host/mvsdio.c
+++ b/drivers/mmc/host/mvsdio.c
@@ -620,9 +620,18 @@ static void mvsd_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
         if (ios->bus_width == MMC_BUS_WIDTH_4)
                 ctrl_reg |= MVSD_HOST_CTRL_DATA_WIDTH_4_BITS;
 
+        /*
+         * The HI_SPEED_EN bit is causing trouble with many (but not all)
+         * high speed SD, SDHC and SDIO cards.  Not enabling that bit
+         * makes all cards work.  So let's just ignore that bit for now
+         * and revisit this issue if problems for not enabling this bit
+         * are ever reported.
+         */
+#if 0
         if (ios->timing == MMC_TIMING_MMC_HS ||
             ios->timing == MMC_TIMING_SD_HS)
                 ctrl_reg |= MVSD_HOST_CTRL_HI_SPEED_EN;
+#endif
 
         host->ctrl = ctrl_reg;
         mvsd_write(MVSD_HOST_CTRL, ctrl_reg);