Re: [Qemu-devel] [PATCH v4 1/7] RTC: Remove the logic to update time format when DM bit changed

[Stefano Stabellini]

On Mon, 19 Mar 2012, Zhang, Yang Z wrote:
> Change DM(date mode) and 24/12 control bit don't affect the internal 
> registers. It only indicates what format is using for those registers. So we 
> don't need to update time format when it is modified.

That might be true, but if the user changes format, then issues a read
RTC_SECONDS, isn't he going to get the old format, unless we call
rtc_copy_date here?



> Signed-off-by: Yang Zhang <address@hidden>
> ---
>  hw/mc146818rtc.c |   10 +---------
>  1 files changed, 1 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
> index a46fdfc..9b49cbc 100644
> --- a/hw/mc146818rtc.c
> +++ b/hw/mc146818rtc.c
> @@ -252,15 +252,7 @@ static void cmos_ioport_write(void *opaque, uint32_t 
> addr, uint32_t data)
>                      rtc_set_time(s);
>                  }
>              }
> -            if (((s->cmos_data[RTC_REG_B] ^ data) & (REG_B_DM | REG_B_24H)) 
> &&
> -                !(data & REG_B_SET)) {
> -                /* If the time format has changed and not in set mode,
> -                   update the registers immediately. */
> -                s->cmos_data[RTC_REG_B] = data;
> -                rtc_copy_date(s);
> -            } else {
> -                s->cmos_data[RTC_REG_B] = data;
> -            }
> +            s->cmos_data[RTC_REG_B] = data;
>              rtc_timer_update(s, qemu_get_clock_ns(rtc_clock));
>              break;
>          case RTC_REG_C:
> --
> 1.7.1
>