Hello. Alan Stern wrote:
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); } }
Instead of removing the PORT_POWER bit from temp, how about re-reading temp from the register after turning off the power? That way the final port status value will be consistent.
OK, will do...
Otherwise this seems okay.
Alan Stern
WBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
