Re: [Qemu-devel] [PATCH 13/31] usb-ehci: drop EXECUTING checks.

[David Ahern <daahern@cisco.com>]

On 06/06/2011 06:39 AM, Gerd Hoffmann wrote:
> The state machine doesn't stop in EXECUTING state any more when async
> packets are in flight, so the checks are not needed any more and can
> be dropped.
> 
> Also kick out the check for the frame timer.  As we don't stop & sleep
> any more on async packets this is obsolete.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/usb-ehci.c |   32 ++------------------------------
>  1 files changed, 2 insertions(+), 30 deletions(-)
> 
> diff --git a/hw/usb-ehci.c b/hw/usb-ehci.c
> index e345a1c..8b1ae3a 100644
> --- a/hw/usb-ehci.c
> +++ b/hw/usb-ehci.c
> @@ -1437,17 +1437,6 @@ static int ehci_state_fetchentry(EHCIState *ehci, int async)
>      int again = 0;
>      uint32_t entry = ehci_get_fetch_addr(ehci, async);
>  
> -#if EHCI_DEBUG == 0
> -    if (qemu_get_clock_ns(vm_clock) / 1000 >= ehci->frame_end_usec) {
> -        if (async) {
> -            DPRINTF("FETCHENTRY: FRAME timer elapsed, exit state machine\n");
> -            goto out;
> -        } else {
> -            DPRINTF("FETCHENTRY: WARNING "
> -                    "- frame timer elapsed during periodic\n");
> -        }
> -    }
> -#endif
>      if (entry < 0x1000) {
>          DPRINTF("fetchentry: entry invalid (0x%08x)\n", entry);
>          ehci_set_state(ehci, async, EST_ACTIVE);
> @@ -1952,12 +1941,6 @@ static void ehci_advance_async_state(EHCIState *ehci)
>          }
>  
>          ehci_set_state(ehci, async, EST_WAITLISTHEAD);
> -        /* fall through */
> -
> -    case EST_FETCHENTRY:
> -        /* fall through */

Why drop this case too? As I recall that is needed for proper execution.

David

> -
> -    case EST_EXECUTING:
>          ehci_advance_state(ehci, async);
>          break;
>  
> @@ -2010,11 +1993,6 @@ static void ehci_advance_periodic_state(EHCIState *ehci)
>          ehci_advance_state(ehci, async);
>          break;
>  
> -    case EST_EXECUTING:
> -        DPRINTF("PERIODIC state adv for executing\n");
> -        ehci_advance_state(ehci, async);
> -        break;
> -
>      default:
>          /* this should only be due to a developer mistake */
>          fprintf(stderr, "ehci: Bad periodic state %d. "
> @@ -2063,11 +2041,7 @@ static void ehci_frame_timer(void *opaque)
>          if (frames - i > 10) {
>              skipped_frames++;
>          } else {
> -            // TODO could this cause periodic frames to get skipped if async
> -            // active?
> -            if (ehci_get_state(ehci, 1) != EST_EXECUTING) {
> -                ehci_advance_periodic_state(ehci);
> -            }
> +            ehci_advance_periodic_state(ehci);
>          }
>  
>          ehci->last_run_usec += FRAME_TIMER_USEC;
> @@ -2082,9 +2056,7 @@ static void ehci_frame_timer(void *opaque)
>      /*  Async is not inside loop since it executes everything it can once
>       *  called
>       */
> -    if (ehci_get_state(ehci, 0) != EST_EXECUTING) {
> -        ehci_advance_async_state(ehci);
> -    }
> +    ehci_advance_async_state(ehci);
>  
>      qemu_mod_timer(ehci->frame_timer, expire_time);
>  }