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EHCI: only power off port if over-current is active

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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 caused 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 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've cut off the port power should be reflected in the result of GetPortStatus
request immediately, hence I'm adding a PORTSCn register readback after write...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: stable@kernel.org
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Sergei Shtylyov 2011-07-06 23:19:38 +04:00 committed by Greg Kroah-Hartman
parent 8dec92b240
commit 81463c1d70
1 changed files with 2 additions and 1 deletions
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3
drivers/usb/host/ehci-hub.c
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@ -816,10 +816,11 @@ 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)){
if ((temp & PORT_OC) && HCS_PPC(ehci->hcs_params)) {
ehci_writel(ehci,
temp & ~(PORT_RWC_BITS | PORT_POWER),
status_reg);
temp = ehci_readl(ehci, status_reg);
}
}