[PATCH] improved TT scheduling for EHCI

[pandora-kernel.git] / drivers / usb / host / Kconfig

diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index e27b79a..c060eb9 100644 (file)
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -47,7 +47,25 @@ 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"