RE: [PATCH 1/5] xhci: Use correct SLOT ID when handling a reset device command

David Laight
2014-06-24T14:06:05Z

From: Of Mathias Nyman
> Command completion events normally include command completion status,
> SLOT_ID, and a pointer to the original command. Reset device command
> completion SLOT_ID may be zero according to xhci specs 4.6.11.
>
> VIA controllers set the SLOT_ID to zero, triggering a WARN_ON in the
> command completion handler.
>
> Use the SLOT ID found from the original command instead.
>
> This patch should be applied to stable kernels since 3.13 that contain
> the commit 20e7acb13ff48fbc884d5918c3697c27de63922a
> "xhci: use completion event's slot id rather than dig it out of command"
>
> Cc: stable@vger.kernel.org # 3.13
> Reported-by: Saran Neti <sarannmr@gmail.com>
> Tested-by: Saran Neti <sarannmr@gmail.com>
> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> ---
> drivers/usb/host/xhci-ring.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index d67ff71..71657d3 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -1433,8 +1433,11 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
> xhci_handle_cmd_reset_ep(xhci, slot_id, cmd_trb, cmd_comp_code);
> break;
> case TRB_RESET_DEV:
> - WARN_ON(slot_id != TRB_TO_SLOT_ID(
> - le32_to_cpu(cmd_trb->generic.field[3])));
> + /* SLOT_ID field in reset device cmd completion event TRB is 0.

Minor nit...
Surely is would be better to say 'is undefined' or 'may be zero'.

David