1 files changed, 19 insertions, 4 deletions

diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index e27b79a3c05f..b93d71d28db7 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -47,12 +47,29 @@ config USB_EHCI_ROOT_HUB_TT
           controller is needed.  It's safe to say "y" even if your
           controller doesn't support this feature.
 
-          This supports the EHCI implementation from TransDimension Inc.
+          This supports the EHCI implementation that's originally
+          from ARC, and has since changed hands a few times.
+
+config USB_EHCI_TT_NEWSCHED
+        bool "Improved Transaction Translator scheduling (EXPERIMENTAL)"
+        depends on USB_EHCI_HCD && EXPERIMENTAL
+        ---help---
+          This changes the periodic scheduling code to fill more of the low
+          and full speed bandwidth available from the Transaction Translator
+          (TT) in USB 2.0 hubs.  Without this, only one transfer will be
+          issued in each microframe, significantly reducing the number of
+          periodic low/fullspeed transfers possible.
+
+          If you have multiple periodic low/fullspeed devices connected to a
+          highspeed USB hub which is connected to a highspeed USB Host
+          Controller, and some of those devices will not work correctly
+          (possibly due to "ENOSPC" or "-28" errors), say Y.
+
+          If unsure, say N.
 
 config USB_ISP116X_HCD
         tristate "ISP116X HCD support"
         depends on USB
-        default N
         ---help---
           The ISP1160 and ISP1161 chips are USB host controllers. Enable this
           option if your board has this chip. If unsure, say N.
@@ -127,7 +144,6 @@ config USB_UHCI_HCD
 config USB_SL811_HCD
         tristate "SL811HS HCD support"
         depends on USB
-        default N
         help
           The SL811HS is a single-port USB controller that supports either
           host side or peripheral side roles.  Enable this option if your
@@ -140,7 +156,6 @@ config USB_SL811_HCD
 config USB_SL811_CS
         tristate "CF/PCMCIA support for SL811HS HCD"
         depends on USB_SL811_HCD && PCMCIA
-        default N
         help
           Wraps a PCMCIA driver around the SL811HS HCD, supporting the RATOC
           REX-CFU1U CF card (often used with PDAs).  If unsure, say N.