Re: [Qemu-devel] Re: [PATCH v3 2/7] wdt_ib700: Don't use SoftFloat int64 type

[Blue Swirl]

On Sun, Dec 19, 2010 at 3:07 PM, Andreas Färber <address@hidden> wrote:
> Am 19.12.2010 um 15:38 schrieb Blue Swirl:
>
>> On Sun, Dec 19, 2010 at 2:28 PM, Andreas Färber <address@hidden>
>> wrote:
>>>
>>> Am 19.12.2010 um 15:16 schrieb Richard W.M. Jones:
>>>
>>>> On Sun, Dec 19, 2010 at 01:51:22PM +0100, Andreas Färber wrote:
>>>>>
>>>>> Am 18.12.2010 um 17:47 schrieb Richard W.M. Jones:
>>>>>
>>>>>> On Sat, Dec 18, 2010 at 05:25:26PM +0100, Andreas Färber wrote:
>>>>>>>
>>>>>>> softfloat.h's int64 type has least-width semantics,
>>>>>>> but this doesn't seem intended here, so use plain int64_t.
>>>>>>>
>>>>>>> v3:
>>>>>>> * Split off.
>>>>>>>
>>>>>>> Cc: Richard W.M. Jones <address@hidden>
>>>>>>> Signed-off-by: Andreas Färber <address@hidden>
>>>>>>> ---
>>>>>>> hw/wdt_ib700.c |    2 +-
>>>>>>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>>>>>>
>>>>>>> diff --git a/hw/wdt_ib700.c b/hw/wdt_ib700.c
>>>>>>> index b6235eb..1248464 100644
>>>>>>> --- a/hw/wdt_ib700.c
>>>>>>> +++ b/hw/wdt_ib700.c
>>>>>>> @@ -53,7 +53,7 @@ static void ib700_write_enable_reg(void *vp,
>>>>>>> uint32_t addr, uint32_t data)
>>>>>>>   30, 28, 26, 24, 22, 20, 18, 16,
>>>>>>>   14, 12, 10,  8,  6,  4,  2,  0
>>>>>>> };
>>>>>>> -    int64 timeout;
>>>>>>> +    int64_t timeout;
>>>>>>>
>>>>>>> ib700_debug("addr = %x, data = %x\n", addr, data);
>>>>>>
>>>>>> The use of int64(_t) was just so that the timeout calculation in the
>>>>>> next two lines would not overflow:
>>>>>>
>>>>>> timeout = (int64_t) time_map[data & 0xF] * get_ticks_per_sec();
>>>>>> qemu_mod_timer(s->timer, qemu_get_clock (vm_clock) + timeout);
>>>>>>
>>>>>> and from you say it does seem like it was a mistake to use int64
>>>>>> instead of int64_t.
>>>>>
>>>>> int64_t should be the right choice then.
>>>>>
>>>>>> ACK.
>>>>>>
>>>>>> In more general terms, am I doing the timeout correctly in this code?
>>>>>
>>>>> Being unfamiliar with both the timer code and this device, hard to
>>>>> say for me.
>>>>> You're taking the lower nibble of uint32_t data and indexing
>>>>> time_map[] with it, which contains 16 elements, so okay, upcast it
>>>>> to 64-bit and multiply it to ticks. Assuming that vm_clock works in
>>>>> ticks, adding the calculated timeout for the next expiry technically
>>>>> looks good. Except for the extra space. ;)
>>>>>
>>>>> Care to provide a formal Reviewed-by or Acked-by? I'd respin it for
>>>>> Blue with updated description.
>>>>
>>>> Is it enough just to write this:
>>>>
>>>> Reviewed-by: Richard W.M. Jones <address@hidden>
>>>> Acked-by: Richard W.M. Jones <address@hidden>
>>>>
>>>> or do you want me to send the updated patch with this added?
>>>
>>> Thanks, that's sufficient! I think of Acked-by as a superset of
>>> Reviewed-by
>>> so I'll go with the former.
>>
>> No, Acked-by tag does not mean much but Reviewed-by carries a lot of
>> weight:
>>
>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/SubmittingPatches;h=689e2371095cc5dfea9927120009341f369159aa;hb=HEAD#l423
>
> So, should I add both or just Reviewed-by or relieve him of the weight? :)

As you wish ;-) I'd suppose that in theory, a patch submitter could
choose to ignore tags offered by untrustworthy reviewers or ackers,
though I don't see much advantage for doing that since they are
sharing some responsibility for the patch.