X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FKconfig.debug;h=900b63c1e899efc48c07d2126c2cf1451eca799f;hb=32665f2bbfed2e325d37236d9b0071a11a69124e;hp=6982094a7e74aa8c5daea87f90878174a8d746c1;hpb=6ffbe7d1fabddc768724656f159759cae7818cd9;p=firefly-linux-kernel-4.4.55.git

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 6982094a7e74..900b63c1e899 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1584,8 +1584,16 @@ config DMA_API_DEBUG
 	  With this option you will be able to detect common bugs in device
 	  drivers like double-freeing of DMA mappings or freeing mappings that
 	  were never allocated.
-	  This option causes a performance degredation.  Use only if you want
-	  to debug device drivers. If unsure, say N.
+
+	  This also attempts to catch cases where a page owned by DMA is
+	  accessed by the cpu in a way that could cause data corruption.  For
+	  example, this enables cow_user_page() to check that the source page is
+	  not undergoing DMA.
+
+	  This option causes a performance degradation.  Use only if you want to
+	  debug device drivers and dma interactions.
+
+	  If unsure, say N.
 
 source "samples/Kconfig"