On 06/06/2011 07:34 AM, David Ahern wrote:
> 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 any more on async packets this is obsolete.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 <kra...@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
This check was added to per Section 4 of the EHCI spec -- the HC should
not start transactions that will not be completed before the end of the
micro-frame. If you remove this what causes the EHCI model to take a
breather?
David
>> 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);
>> }
