Re: [PATCH v2 10/10] usb/msd: Add more tracing

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 11/4/25 10:04, Nicholas Piggin wrote:
> Add tracing for more received packet types, cbw_state changes, and
> some more SCSI callbacks. These were useful in debugging relaxed
> packet ordering support.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>   hw/usb/dev-storage.c | 23 +++++++++++++++++++++--
>   hw/usb/trace-events  |  9 ++++++++-
>   2 files changed, 29 insertions(+), 3 deletions(-)


>   static void usb_msd_copy_data(MSDState *s, USBPacket *p)
>   {
>       uint32_t len;
> +
>       len = p->iov.size - p->actual_length;
> +
> +    trace_usb_msd_copy_data(s->req->tag, len);
> +
>       if (len > s->scsi_len)
>           len = s->scsi_len;
>       usb_packet_copy(p, scsi_req_get_buf(s->req) + s->scsi_off, len);
> @@ -264,6 +268,8 @@ void usb_msd_transfer_data(SCSIRequest *req, uint32_t len)
>       MSDState *s = DO_UPCAST(MSDState, dev.qdev, req->bus->qbus.parent);
>       USBPacket *p = s->data_packet;
>   
> +    trace_usb_msd_transfer_data(req->tag, len);
> +
>       if (s->cbw_state == USB_MSD_CBW_DATAIN) {
>           if (req->cmd.mode == SCSI_XFER_TO_DEV) {
>               usb_msd_fatal_error(s);
> @@ -324,11 +330,13 @@ void usb_msd_command_complete(SCSIRequest *req, size_t resid)
>           }
>           if (s->data_len == 0) {
>               s->cbw_state = USB_MSD_CBW_CSW;
> +            trace_usb_msd_cbw_state(s->cbw_state);
>           }
>           /* USB_RET_SUCCESS status clears previous ASYNC status */
>           usb_msd_data_packet_complete(s, USB_RET_SUCCESS);
>       } else if (s->data_len == 0) {
>           s->cbw_state = USB_MSD_CBW_CSW;
> +        trace_usb_msd_cbw_state(s->cbw_state);
>       }

Maybe helpful to log state transition?

   void usb_msd_cbw_change_state(MSDState *s,
                                 enum USBMSDCBWState cbw_state)
   {
       if (s->cbw_state != cbw_state) {
           trace_usb_msd_cbw_state(s->cbw_state, cbw_state);
           s->cbw_state = cbw_state;
       }
   }

Otherwise,
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>