Le 27/09/2016 à 15:22, Greg Ungerer a écrit : > Hi Laurent, > > On 27/09/16 18:11, Laurent Vivier wrote: >> Le 27/09/2016 à 09:33, Thomas Huth a écrit : >>> On 27.09.2016 03:29, Greg Ungerer wrote: >>>> The shipping default setting for the Freescale M5208EVB board is to run >>>> the CPU at 166MHz. The current qemu emulation code for this board is >>>> defaulting to 66MHz. This results in time appearing to run way to >>>> slowly. >>>> So a "sleep 5" in a standard ColdFire Linux build takes almost 15 >>>> seconds in real time to actually complete. >>>> >>>> Change the hard coded default to match the default hardware setting. >>>> >>>> Signed-off-by: Greg Ungerer <g...@uclinux.org> >>>> --- >>>> hw/m68k/mcf5208.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/hw/m68k/mcf5208.c b/hw/m68k/mcf5208.c >>>> index 9240ebf..2d0b464 100644 >>>> --- a/hw/m68k/mcf5208.c >>>> +++ b/hw/m68k/mcf5208.c >>>> @@ -21,7 +21,7 @@ >>>> #include "elf.h" >>>> #include "exec/address-spaces.h" >>>> >>>> -#define SYS_FREQ 66000000 >>>> +#define SYS_FREQ 166000000 >>> >>> Good catch. But actually, the M5208EVB User's Manual talks about 166.67 >>> MHz, so while you're at it, maybe you should change it to 166666666 >>> instead? >> >> In this case, it should be better to use a period of 6000000 ns (and >> ptimer_set_period() instead of ptimer_set_freq()). > > Why is that better in this case? > All the documentation lists it as 166.67MHz, even on the PCB. > Isn't it clearer to define it based on the actual value documented?
It is better because 166.67 MHZ is clearly a rounded value computed from the period: 1000000000/6000000 = 166.666666666666666666666666... And internally QEMU uses the period, not the frequency. Laurent
