Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [30/50] EHCI: only power off port if over-current is active | Date | Thu, 28 Jul 2011 16:44:34 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
[ 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>
Index: linux-2.6.35.y/drivers/usb/host/ehci-hub.c =================================================================== --- linux-2.6.35.y.orig/drivers/usb/host/ehci-hub.c +++ linux-2.6.35.y/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); } }
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