Re: [PATCH 1/1] usb: xhci: handle Config Error Change (CEC) in xhci driver

From: Mathias Nyman
Date: Thu Mar 12 2015 - 10:30:58 EST

On 06.03.2015 10:12, Lu Baolu wrote:
> Linux xHCI driver doesn't report and handle port cofig error change.
> If Port Configure Error for root hub port occurs, CEC bit in PORTSC
> would be set by xHC and remains 1. This happends when the root port
> fails to configure its link partner, e.g. the port fails to exchange
> port capabilities information using Port Capability LMPs.
> Then the Port Status Change Events will be blocked until all status
> change bits(CEC is one of the change bits) are cleared('0') (refer to
> xHCI spec 4.19.2). Otherwise, the port status change event for this
> root port will not be generated anymore, then root port would look
> like dead for user and can't be recovered until a Host Controller
> Reset(HCRST).
> This patch is to check CEC bit in PORTSC in xhci_get_port_status()
> and set a Config Error in the return status if CEC is set. This will
> cause a ClearPortFeature request, where CEC bit is cleared in
> xhci_clear_port_change_bit().
> [Mathias Nyman contributed the idea. The commit log is based on patch
> posted at]
> Signed-off-by: Lu Baolu <>
> Cc: stable <stable@xxxxxxxxxxxxxxx> # v3.2+

Looks good, I'll add it to the queue,

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at