On Thu, Mar 17, 2011 at 10:47:46PM +0300, Dan Carpenter wrote:
> Btw, xhci-ring.c causes some valid looking gcc warnings:
>
> C [M] drivers/usb/host/xhci-ring.o
> drivers/usb/host/xhci-ring.c: In function âhandle_port_statusâ:
> drivers/usb/host/xhci-ring.c:1229: warning: âhcdâ may be used uninitialized in this function
> drivers/usb/host/xhci-ring.c: In function âhandle_tx_eventâ:
> drivers/usb/host/xhci-ring.c:1895: warning: âevent_trbâ may be used uninitialized in this function
Oh, actually, looking through my mail, Dmitry also noticed the event_trb
issue last week and started on a patch to fix it (see below).
Dmitry, can you please send a proper patch?
Thanks,
Sarah Sharp
On Wed, Feb 23, 2011 at 08:48:02PM -0800, Dmitry Torokhov wrote:
> Hi Andiry, Sarah,
>
> I was compiling xhci and got a warning that event_trb might be used
> uninitialized in handle_tx_event(). Looking at the implementation the
> logic is quite convoluted but appears that if the following condition is
> true:
>
> !event_seg && ep->skip && usb_endpoint_xfer_isoc(...)
>
> we indeed will end up calling process_*_td(..., event_trb, ...).
>
> I think something like the following is needed...
>
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 3e8211c..85ae5ef 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -1918,22 +1918,26 @@ static int handle_tx_event(struct xhci_hcd *xhci,
> }
>
> td = list_entry(ep_ring->td_list.next, struct xhci_td, td_list);
> +
> /* Is this a TRB in the currently executing TD? */
> event_seg = trb_in_td(ep_ring->deq_seg, ep_ring->dequeue,
> td->last_trb, event_dma);
> - if (event_seg && ep->skip) {
> - xhci_dbg(xhci, "Found td. Clear skip flag.\n");
> - ep->skip = false;
> - }
> - if (!event_seg &&
> - (!ep->skip || !usb_endpoint_xfer_isoc(&td->urb->ep->desc))) {
> + if (!event_seg) {
> + if (ep->skip &&
> + usb_endpoint_xfer_isoc(&td->urb->ep->desc)) {
> + ret = 0;
> + goto cleanup;
> + }
> /* HC is busted, give up! */
> - xhci_err(xhci, "ERROR Transfer event TRB DMA ptr not "
> - "part of current TD\n");
> + xhci_err(xhci,
> + "ERROR Transfer event TRB DMA ptr not part of current TD\n");
> return -ESHUTDOWN;
> - }
> + } else {
> + if (ep->skip) {
> + xhci_dbg(xhci, "Found td. Clear skip flag.\n");
> + ep->skip = false;
> + }
>
> - if (event_seg) {
> event_trb = &event_seg->trbs[(event_dma -
> event_seg->dma) / sizeof(*event_trb)];
> /*
>
> Thanks.
>
> --
> Dmitry
>
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