Commit 42df7215 authored by Lu Baolu's avatar Lu Baolu Committed by Greg Kroah-Hartman
Browse files

usb: xhci: fix checking ep busy for CFC 



Function ep_ring_is_processing() checks the dequeue pointer
in endpoint context to know whether an endpoint is busy with
processing TRBs. This is not correct since dequeue pointer
field in an endpoint context is only valid when the endpoint
is in Halted or Stopped states. This buggy code causes audio
noise when playing sound with USB headset connected to host
controllers which support CFC (one of xhci 1.1 features).

This patch should exist in stable kernel since v4.3.

Reported-and-tested-by: default avatarYD Tseng <yd_tseng@asmedia.com.tw>
Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Cc: stable <stable@vger.kernel.org> # v4.3
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a5964396

drivers/usb/host/xhci-ring.c

+6 −26
Original line number Diff line number Diff line
@@ -3896,28 +3896,6 @@ cleanup: 
	return ret;

}



static int ep_ring_is_processing(struct xhci_hcd *xhci,

		int slot_id, unsigned int ep_index)

{

	struct xhci_virt_device *xdev;

	struct xhci_ring *ep_ring;

	struct xhci_ep_ctx *ep_ctx;

	struct xhci_virt_ep *xep;

	dma_addr_t hw_deq;



	xdev = xhci->devs[slot_id];

	xep = &xhci->devs[slot_id]->eps[ep_index];

	ep_ring = xep->ring;

	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);



	if ((le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK) != EP_STATE_RUNNING)

		return 0;



	hw_deq = le64_to_cpu(ep_ctx->deq) & ~EP_CTX_CYCLE_MASK;

	return (hw_deq !=

		xhci_trb_virt_to_dma(ep_ring->enq_seg, ep_ring->enqueue));

}



/*

 * Check transfer ring to guarantee there is enough room for the urb.

 * Update ISO URB start_frame and interval.
@@ -3983,11 +3961,13 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci, gfp_t mem_flags, 
	}



	/* Calculate the start frame and put it in urb->start_frame. */

	if (HCC_CFC(xhci->hcc_params) &&

			ep_ring_is_processing(xhci, slot_id, ep_index)) {

	if (HCC_CFC(xhci->hcc_params) && !list_empty(&ep_ring->td_list)) {

		if ((le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK) ==

				EP_STATE_RUNNING) {

			urb->start_frame = xep->next_frame_id;

			goto skip_start_over;

		}

	}



	start_frame = readl(&xhci->run_regs->microframe_index);

	start_frame &= 0x3fff;

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