diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2007-01-16 11:59:45 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-02-07 15:44:37 -0800 |
| commit | 57e06c11372eccf5acebdd4664eb025fee76c561 (patch) | |
| tree | a792559056735005ce7037196509fb151d3c3bc5 /drivers/usb/host/ehci-hcd.c | |
| parent | 625b5c9a0069ef1b61feb3ce599b39f1b04b5666 (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.c | 2 |
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; } |