Re: [Qemu-devel] [PATCH v8 3/4] hw/ptimer: Update .delta on period/freq change

[Peter Crosthwaite]

On Tue, Jan 05, 2016 at 05:33:28AM +0300, Dmitry Osipenko wrote:
> Delta value must be updated on period/freq change, otherwise running timer
> would be restarted (counter reloaded with old delta). Only m68k/mcf520x
> and arm/arm_timer devices are currently doing freq change correctly, i.e.
> stopping the timer. Perform delta update to fix affected devices and
> eliminate potential further mistakes.
> 
> Signed-off-by: Dmitry Osipenko 

Reviewed-by: Peter Crosthwaite 

> ---
>  hw/core/ptimer.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
> index 96a6c7a..8c2dd9f 100644
> --- a/hw/core/ptimer.c
> +++ b/hw/core/ptimer.c
> @@ -207,6 +207,7 @@ void ptimer_stop(ptimer_state *s)
>  /* Set counter increment interval in nanoseconds.  */
>  void ptimer_set_period(ptimer_state *s, int64_t period)
>  {
> +s->delta = ptimer_get_count(s);
>  s->period = period;
>  s->period_frac = 0;
>  if (s->enabled) {
> @@ -218,6 +219,7 @@ void ptimer_set_period(ptimer_state *s, int64_t period)
>  /* Set counter frequency in Hz.  */
>  void ptimer_set_freq(ptimer_state *s, uint32_t freq)
>  {
> +s->delta = ptimer_get_count(s);
>  s->period = 10ll / freq;
>  s->period_frac = (10ll << 32) / freq;
>  if (s->enabled) {
> -- 
> 2.6.4
> 

[Qemu-devel] [PATCH v8 3/4] hw/ptimer: Update .delta on period/freq change

[Dmitry Osipenko]

Delta value must be updated on period/freq change, otherwise running timer
would be restarted (counter reloaded with old delta). Only m68k/mcf520x
and arm/arm_timer devices are currently doing freq change correctly, i.e.
stopping the timer. Perform delta update to fix affected devices and
eliminate potential further mistakes.

Signed-off-by: Dmitry Osipenko 
---
 hw/core/ptimer.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
index 96a6c7a..8c2dd9f 100644
--- a/hw/core/ptimer.c
+++ b/hw/core/ptimer.c
@@ -207,6 +207,7 @@ void ptimer_stop(ptimer_state *s)
 /* Set counter increment interval in nanoseconds.  */
 void ptimer_set_period(ptimer_state *s, int64_t period)
 {
+s->delta = ptimer_get_count(s);
 s->period = period;
 s->period_frac = 0;
 if (s->enabled) {
@@ -218,6 +219,7 @@ void ptimer_set_period(ptimer_state *s, int64_t period)
 /* Set counter frequency in Hz.  */
 void ptimer_set_freq(ptimer_state *s, uint32_t freq)
 {
+s->delta = ptimer_get_count(s);
 s->period = 10ll / freq;
 s->period_frac = (10ll << 32) / freq;
 if (s->enabled) {
-- 
2.6.4