MAX4967 USB power supply chip we use on our boards signals over-current when
power is not enabled; once it's enabled, over-current signal returns to normal.
That unfortunately causes the endless stream of "over-current change on port"
messages. The EHCI root hub code reacts on every over-current signal change
with powering off the port -- such change event is generated the moment the
port power is enabled, so once enabled the power is immediately cut off.
I think we should only cut off power only when we're seeing the active over-
current signal, so I'm adding such check to that code. I also think that the
fact that we shut off the port power should be reflected in the result of
GetPortStatus() immediately, hence I'm also changing the place where the
PORT_POWER bit is cleared...
Signed-off-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxx
---
The patch is against the 'usb-linus' branch of Greg KH's usb-2.6.git...
drivers/usb/host/ehci-hub.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
Index: usb-2.6/drivers/usb/host/ehci-hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/host/ehci-hub.c
+++ usb-2.6/drivers/usb/host/ehci-hub.c
@@ -891,10 +891,10 @@ static int ehci_hub_control (
* power switching; they're allowed to just limit the
* current. khubd will turn the power back on.
*/
- if (HCS_PPC (ehci->hcs_params)){
- ehci_writel(ehci,
- temp & ~(PORT_RWC_BITS | PORT_POWER),
- status_reg);
+ if ((temp & PORT_OC) && HCS_PPC(ehci->hcs_params)) {
+ temp &= ~PORT_POWER;
+ ehci_writel(ehci, temp & ~PORT_RWC_BITS,
+ status_reg);
}
}
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