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