[PATCH] mmc: don't use DMA on newer ENE controllers

From: Pierre Ossman
Date: Fri Jul 04 2008 - 06:51:40 EST


From: Pierre Ossman <drzeus@xxxxxxxxx>

Even the newer ENE controllers have bugs in their DMA engine that make
it too dangerous to use. Disable it until someone has figured out under
which conditions it corrupts data.

This has caused problems at least once, and can be found as bug report
10925 in the kernel bugzilla.

Signed-off-by: Pierre Ossman <drzeus@xxxxxxxxx>

--

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 07c2048..116abf2 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -115,7 +115,8 @@ static const struct pci_device_id pci_ids[] __devinitdata = {
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,
.driver_data = SDHCI_QUIRK_SINGLE_POWER_WRITE |
- SDHCI_QUIRK_RESET_CMD_DATA_ON_IOS,
+ SDHCI_QUIRK_RESET_CMD_DATA_ON_IOS |
+ SDHCI_QUIRK_BROKEN_DMA,
},

{
@@ -124,7 +125,8 @@ static const struct pci_device_id pci_ids[] __devinitdata = {
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,
.driver_data = SDHCI_QUIRK_SINGLE_POWER_WRITE |
- SDHCI_QUIRK_RESET_CMD_DATA_ON_IOS,
+ SDHCI_QUIRK_RESET_CMD_DATA_ON_IOS |
+ SDHCI_QUIRK_BROKEN_DMA,
},

{

--
-- Pierre Ossman

Linux kernel, MMC maintainer http://www.kernel.org
rdesktop, core developer http://www.rdesktop.org

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