Re: [PATCH v2 1/1] usb: xhci: fix checking ep busy for CFC

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello.

On 10/29/2015 5:46 AM, Lu Baolu wrote:

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: YD Tseng <yd_tseng@xxxxxxxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

---
v1->v2:
Implement the logic in xhci_queue_isoc_tx_prepare() instead of
a seperated function as suggested by Mathias.

---
  drivers/usb/host/xhci-ring.c | 32 ++++++--------------------------
  1 file changed, 6 insertions(+), 26 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index fa83625..8edc286 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
[...]
@@ -3983,10 +3961,12 @@ 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)) {
-		urb->start_frame = xep->next_frame_id;
-		goto skip_start_over;
+	if (HCC_CFC(xhci->hcc_params)) {
+		if ((le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK)
+					== EP_STATE_RUNNING &&
+				!list_empty(&ep_ring->td_list))
+			urb->start_frame = xep->next_frame_id;
+			goto skip_start_over;

   Forgot {}?

  	}

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

MBR, Sergei

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux