From 57e06c11372eccf5acebdd4664eb025fee76c561 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 16 Jan 2007 11:59:45 -0500 Subject: EHCI: force high-speed devices to run at full speed This patch (as710) adds a sysfs class-device attribute file named "companion" for EHCI controllers. The file contains a list of port numbers that are dedicated to the companion controller; by writing a port number to the file the user can force a high-speed device attached directly to the computer to run at full speed. (As far as I know it is not possible to do this for a device attached to an external hub.) A port is removed from the file by writing the negative of its port number. Several users have asked for this facility and it seems like a useful thing to have. Every now and then one runs across a device which behaves much better at full speed than at high speed. Signed-off-by: Alan Stern Cc: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-hcd.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/usb/host/ehci-hcd.c') diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index 9ec896218fe..92c62911f57 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -388,6 +388,7 @@ static void ehci_stop (struct usb_hcd *hcd) /* let companion controllers work when we aren't */ ehci_writel(ehci, 0, &ehci->regs->configured_flag); + remove_companion_file(ehci); remove_debug_files (ehci); /* root hub is shut down separately (first, when possible) */ @@ -563,6 +564,7 @@ static int ehci_run (struct usb_hcd *hcd) * since the class device isn't created that early. */ create_debug_files(ehci); + create_companion_file(ehci); return 0; } -- cgit v1.2.3