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Date: Wed, 19 Oct 2016 09:52:52 +0300
From: Mathias Nyman <mathias.nyman@...ux.intel.com>
To: Lu Baolu <baolu.lu@...ux.intel.com>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] usb: xhci: clean up error_bitmask usage
Hi
On 19.10.2016 03:53, Lu Baolu wrote:
> In xhci_handle_event(), when errors are detected, driver always sets
> a bit in error_bitmask (one member of the xhci private driver data).
> That means users have to retrieve and decode the value of error_bitmask
> in xhci private driver data if they want to know whether those erros
> ever happened in xhci_handle_event(). Otherwise, those errors are just
> ignored silently.
>
> This patch cleans up this by replacing the setting of error_bitmask
> with the kernel print functions, so that users can easily check and
> report the errors happened in xhci_handle_event().
>
> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
Nice to get this cleaned out. I think the error_bitmask was something
used during driver development but has no function anymore.
A few minor comments below
> ---
> drivers/usb/host/xhci-ring.c | 42 +++++++++++++++++++-----------------------
> drivers/usb/host/xhci.h | 2 --
> 2 files changed, 19 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 797137e..a460423 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -1183,7 +1183,7 @@ static void xhci_handle_cmd_nec_get_fw(struct xhci_hcd *xhci,
> struct xhci_event_cmd *event)
> {
> if (!(xhci->quirks & XHCI_NEC_HOST)) {
> - xhci->error_bitmask |= 1 << 6;
> + xhci_warn(xhci, "WARN NEC_GET_FW command on non-NEC host\n");
> return;
> }
> xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
> @@ -1325,14 +1325,13 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
> cmd_trb = xhci->cmd_ring->dequeue;
> cmd_dequeue_dma = xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
> cmd_trb);
> - /* Is the command ring deq ptr out of sync with the deq seg ptr? */
> - if (cmd_dequeue_dma == 0) {
> - xhci->error_bitmask |= 1 << 4;
> - return;
> - }
> - /* Does the DMA address match our internal dequeue pointer address? */
> - if (cmd_dma != (u64) cmd_dequeue_dma) {
> - xhci->error_bitmask |= 1 << 5;
> + /*
> + * Check whether the completion event is for our internal kept
> + * command.
> + */
> + if (!cmd_dequeue_dma || cmd_dma != (u64)cmd_dequeue_dma) {
> + xhci_warn(xhci,
> + "ERROR mismatched command completion event\n");
> return;
> }
>
> @@ -1418,7 +1417,7 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
> break;
> default:
> /* Skip over unknown commands on the event ring */
> - xhci->error_bitmask |= 1 << 6;
> + xhci_info(xhci, "INFO unknown command type %d\n", cmd_type);
> break;
> }
>
> @@ -1521,7 +1520,7 @@ static void handle_port_status(struct xhci_hcd *xhci,
> /* Port status change events always have a successful completion code */
> if (GET_COMP_CODE(le32_to_cpu(event->generic.field[2])) != COMP_SUCCESS) {
> xhci_warn(xhci, "WARN: xHC returned failed port status event\n");
> - xhci->error_bitmask |= 1 << 8;
> + return;
I don't think we should return here, it will mess up the event ring dequeue pointer.
And a non-expected completion code here should not prevent us from working normally
> }
> port_id = GET_PORT_ID(le32_to_cpu(event->generic.field[0]));
> xhci_dbg(xhci, "Port Status Change Event for port %d\n", port_id);
> @@ -2642,20 +2641,18 @@ static int xhci_handle_event(struct xhci_hcd *xhci)
> {
> union xhci_trb *event;
> int update_ptrs = 1;
> - int ret;
>
> + /* Event ring hasn't been allocated yet. */
> if (!xhci->event_ring || !xhci->event_ring->dequeue) {
> - xhci->error_bitmask |= 1 << 1;
> - return 0;
> + xhci_err(xhci, "ERROR event ring not ready\n");
> + return -ENOMEM;
> }
>
> event = xhci->event_ring->dequeue;
> /* Does the HC or OS own the TRB? */
> if ((le32_to_cpu(event->event_cmd.flags) & TRB_CYCLE) !=
> - xhci->event_ring->cycle_state) {
> - xhci->error_bitmask |= 1 << 2;
> + xhci->event_ring->cycle_state)
> return 0;
> - }
>
> /*
> * Barrier between reading the TRB_CYCLE (valid) flag above and any
> @@ -2663,7 +2660,7 @@ static int xhci_handle_event(struct xhci_hcd *xhci)
> */
> rmb();
> /* FIXME: Handle more event types. */
> - switch ((le32_to_cpu(event->event_cmd.flags) & TRB_TYPE_BITMASK)) {
> + switch (le32_to_cpu(event->event_cmd.flags) & TRB_TYPE_BITMASK) {
> case TRB_TYPE(TRB_COMPLETION):
> handle_cmd_completion(xhci, &event->event_cmd);
> break;
> @@ -2672,10 +2669,7 @@ static int xhci_handle_event(struct xhci_hcd *xhci)
> update_ptrs = 0;
> break;
> case TRB_TYPE(TRB_TRANSFER):
> - ret = handle_tx_event(xhci, &event->trans_event);
> - if (ret < 0)
> - xhci->error_bitmask |= 1 << 9;
> - else
> + if (!handle_tx_event(xhci, &event->trans_event))
> update_ptrs = 0;
had to check this, it works because handle_tx_event() doesn't return positive values.
> break;
> case TRB_TYPE(TRB_DEV_NOTE):
> @@ -2686,7 +2680,9 @@ static int xhci_handle_event(struct xhci_hcd *xhci)
> TRB_TYPE(48))
> handle_vendor_event(xhci, event);
> else
> - xhci->error_bitmask |= 1 << 3;
> + xhci_warn(xhci, "ERROR unknown event type %d\n",
> + le32_to_cpu(event->event_cmd.flags) &
> + TRB_TYPE_BITMASK);
This trb type is still shifted 10 bits when printing it out.
There are not yet any proper helpers or macros for this it seems
-Mathias
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