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-rw-r--r--drivers/mmc/card/Kconfig18
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/mmc/card/Kconfig b/drivers/mmc/card/Kconfig
index 9320a8c7323..a49cb9737cd 100644
--- a/drivers/mmc/card/Kconfig
+++ b/drivers/mmc/card/Kconfig
@@ -14,3 +14,21 @@ config MMC_BLOCK
mount the filesystem. Almost everyone wishing MMC support
should say Y or M here.
+config MMC_BLOCK_BOUNCE
+ bool "Use bounce buffer for simple hosts"
+ depends on MMC_BLOCK
+ default y
+ help
+ SD/MMC is a high latency protocol where it is crucial to
+ send large requests in order to get high performance. Many
+ controllers, however, are restricted to continuous memory
+ (i.e. they can't do scatter-gather), something the kernel
+ rarely can provide.
+
+ Say Y here to help these restricted hosts by bouncing
+ requests back and forth from a large buffer. You will get
+ a big performance gain at the cost of up to 64 KiB of
+ physical memory.
+
+ If unsure, say Y here.
+