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| author | Sergei Shtylyov <sshtylyov@ru.mvista.com> | 2011-07-06 23:19:38 +0400 |
|---|---|---|
| committer | Andi Kleen <ak@linux.intel.com> | 2011-08-01 13:55:02 -0700 |
| commit | 81da73dccac71cbbd5949f87a7cacf2925f01e44 (patch) | |
| tree | e30c2cd40cd3d8b4e68aff216506c6b323bc0d40 | |
| parent | 8f8d6bc6ec9510a3bd8d97e011c7dc6008a7355d (diff) | |
| download | lwn-81da73dccac71cbbd5949f87a7cacf2925f01e44.tar.gz lwn-81da73dccac71cbbd5949f87a7cacf2925f01e44.zip | |
EHCI: only power off port if over-current is active
[ upstream commit 81463c1d707186adbbe534016cd1249edeab0dac ]
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>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
| -rw-r--r-- | drivers/usb/host/ehci-hub.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c index e7d3d8def282..34053e795a83 100644 --- a/drivers/usb/host/ehci-hub.c +++ b/drivers/usb/host/ehci-hub.c @@ -837,10 +837,11 @@ 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); } } |