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Re: [Qemu-devel] [PATCH] hw/ptimer: Don't wrap around counter for expire
From: |
Dmitry Osipenko |
Subject: |
Re: [Qemu-devel] [PATCH] hw/ptimer: Don't wrap around counter for expired timer that uses tick handler |
Date: |
Sat, 25 Jun 2016 15:20:53 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 25.06.2016 13:04, Mark Cave-Ayland wrote:
> On 24/06/16 21:29, Dmitry Osipenko wrote:
>
>> Software should see timer counter wrap around only after IRQ being triggered.
>> Change returned counter value to "1" for the expired timer and avoid
>> returning
>> wrapped around counter value in periodic mode for the timer that has
>> bottom-half
>> handler setup, assuming it is IRQ handler.
>>
>> This fixes regression introduced by the commit 5a50307 ("hw/ptimer: Perform
>> counter wrap around if timer already expired") on SPARC emulated machine as
>> reported by Mark Cave-Ayland.
>>
>> Signed-off-by: Dmitry Osipenko <address@hidden>
>> ---
>> hw/core/ptimer.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
>> index 7f89001..620ac2e 100644
>> --- a/hw/core/ptimer.c
>> +++ b/hw/core/ptimer.c
>> @@ -98,10 +98,10 @@ uint64_t ptimer_get_count(ptimer_state *s)
>> bool oneshot = (s->enabled == 2);
>>
>> /* Figure out the current counter value. */
>> - if (expired && (oneshot || use_icount)) {
>> + if (expired && (oneshot || use_icount || s->bh != NULL)) {
>> /* Prevent timer underflowing if it should already have
>> triggered. */
>> - counter = 0;
>> + counter = 1;
>> } else {
>> uint64_t rem;
>> uint64_t div;
>> @@ -148,7 +148,9 @@ uint64_t ptimer_get_count(ptimer_state *s)
>>
>> if (expired && counter != 0) {
>> /* Wrap around periodic counter. */
>> - counter = s->limit - (counter - 1) % s->limit;
>> + counter = s->delta = s->limit - (counter - 1) % s->limit;
>> + /* Re-arm timer according to the wrapped around value. */
>> + ptimer_reload(s);
>> }
>> }
>> } else {
>>
>
> Hi Dmitry,
>
> Thanks for the patch, however I am unable to apply this to git master with git
> am or directly using patch:
>
> $ patch -p1 < timer.eml
> (Stripping trailing CRs from patch.)
> patching file hw/core/ptimer.c
> Hunk #1 FAILED at 98.
> Hunk #2 succeeded at 143 (offset -5 lines).
> 1 out of 2 hunks FAILED -- saving rejects to file hw/core/ptimer.c.rej
>
> Does it need to be rebased before it can be applied?
>
>
> ATB,
>
> Mark.
>
Yes, but it's my overlook. I made it on top of tainted branch, will send V2.
Sorry and thanks for trying it and letting me know.
--
Dmitry