Re: [Qemu-devel] RTC polling mode broken

[Bernhard Kauer]

Suppose I have some software that does not run with Qemu 
and I have done the following steps:

        1. found that it is bug in Qemu and not in my software
        2. produced a patch that fixed the problem for my test-case
        3. send the patch with an explanation to the mailinglist
        4. waited 6 weeks for comments or inclusion in Qemu

Now what should I do, to get the bug fixed?


Thanks,


        Bernhard




On Wed, Jul 15, 2009 at 12:50:43PM +0200, Bernhard Kauer wrote:
> The RTC emulation does not set the IRQ flags independent of the IRQ enable 
> bits.
> 
> The original MC146818A datasheet from 1984 notes:
>       "flag bits in Register C [...] are set independent of the
>       state of the corresponding enable bits in Register B"
> Similar sections can be found in newer documentation e.g. in rtc82885.
> 
> Qemu and Bochs set the IRQ flags only if they are enabled,
> which breaks drivers polling on them.
> 
> The following patch corrects this for the update-ended-flag in Qemu only.
> It currently does not fix the handling of the other flags.
> 
> 
> Signed-off-by: Bernhard Kauer <address@hidden>
> 
> 
> diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
> index 2022548..2b040a7 100644
> --- a/hw/mc146818rtc.c
> +++ b/hw/mc146818rtc.c
> @@ -421,9 +421,10 @@ static void rtc_update_second2(void *opaque)
>      }
>  
>      /* update ended interrupt */
> +    s->cmos_data[RTC_REG_C] |= REG_C_UF;
>      if (s->cmos_data[RTC_REG_B] & REG_B_UIE) {
> -        s->cmos_data[RTC_REG_C] |= 0x90;
> -        rtc_irq_raise(s->irq);
> +      s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
> +      rtc_irq_raise(s->irq);
>      }
>  
>      /* clear update in progress bit */