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authorAlan Stern <stern@rowland.harvard.edu>2007-01-16 11:59:45 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2007-02-07 15:44:37 -0800
commit57e06c11372eccf5acebdd4664eb025fee76c561 (patch)
treea792559056735005ce7037196509fb151d3c3bc5 /drivers/usb/host/ehci-hcd.c
parent625b5c9a0069ef1b61feb3ce599b39f1b04b5666 (diff)
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 <stern@rowland.harvard.edu> Cc: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host/ehci-hcd.c')
-rw-r--r--drivers/usb/host/ehci-hcd.c2
1 files changed, 2 insertions, 0 deletions
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;
}