Re: [Qemu-devel] [PATCH] configure: make it possible to disable IASL

[Stefan Weil]

Am 24.11.2013 17:48, schrieb Michael S. Tsirkin:
> On Sun, Nov 24, 2013 at 05:39:58PM +0200, Michael S. Tsirkin wrote:
>> On Sun, Nov 24, 2013 at 02:54:51PM +0100, Stefan Weil wrote:
>>> Am 24.11.2013 14:42, schrieb Michael S. Tsirkin:
>>>> On Sun, Nov 24, 2013 at 03:04:04PM +0200, Marcel Apfelbaum wrote:
>>>>> On Sun, 2013-11-24 at 11:52 +0200, Michael S. Tsirkin wrote:
>>>>>> Useful for platforms with a broken IASL.
>>>>>>
>>>>>> Signed-off-by: Michael S. Tsirkin <address@hidden>
>>>>>> ---
>>>>>>  configure | 3 ++-
>>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/configure b/configure
>>>>>> index 0592ba7..d0a0abe 100755
>>>>>> --- a/configure
>>>>>> +++ b/configure
>>>>>> @@ -1080,6 +1080,7 @@ echo "  --source-path=PATH       path of source 
>>>>>> code [$source_path]"
>>>>>>  echo "  --cross-prefix=PREFIX    use PREFIX for compile tools 
>>>>>> [$cross_prefix]"
>>>>>>  echo "  --cc=CC                  use C compiler CC [$cc]"
>>>>>>  echo "  --iasl=IASL              use ACPI compiler IASL [$iasl]"
>>>>>> +echo "                           iasl='' (empty string) disables ACPI 
>>>>>> compiler"
>>>>>>  echo "  --host-cc=CC             use C compiler CC [$host_cc] for code 
>>>>>> run at"
>>>>>>  echo "                           build time"
>>>>>>  echo "  --cxx=CXX                use C++ compiler CXX [$cxx]"
>>>>>> @@ -4269,7 +4270,7 @@ else
>>>>>>  fi
>>>>>>  echo "PYTHON=$python" >> $config_host_mak
>>>>>>  echo "CC=$cc" >> $config_host_mak
>>>>>> -if $iasl -h > /dev/null 2>&1; then
>>>>>> +if test "$iasl" && $iasl -h > /dev/null 2>&1; then
>>>>>>    echo "IASL=$iasl" >> $config_host_mak
>>>>>>  fi
>>>>>>  echo "CC_I386=$cc_i386" >> $config_host_mak
>>>>> I tried to disable iasl without this patch and it worked for me...
>>>>> I used:
>>>>>     - [Qemu-devel] [PATCH] configure: make --iasl option actually work
>>>>>     - ./configure --iasl="" (or --iasl=)
>>>>> and it worked (no sign of IASL in config-host.mak)
>>>>>
>>>>> I think this is because the prev test "$iasl -h > /dev/null 2>&1"
>>>>> fails of course.
>>>> By luck, yes.
>>>>
>>>> So this is just a documentation patch: cleaner to document the
>>>> interface explicitly.
>>>> I'll make this clearer in the commit log.
>>>>
>>> --iasl=false works without further modifications (because test "false
>>> -h" works and returns false). It also looks more natural than --iasl=.
>>>
>>> Cheers, Stefan
>> It seems that some people try --iasl= as the more natural way
>> to do this. It's not documented that a failing iasl will
>> cause a fall-back and I'd rather document an explicit option
>> than making it fail.
> I'm also curious why would you say =false is natural:
> it's a string option not a boolean one.
>

'false' is a string here, namely the name of the executable which is
normally found at /bin/false.
It takes any number of parameters and always returns 1 (which is boolean
false
in shell conventions).

You could also write --iasl=/bin/false.

I suggest this kind of patch:

 echo "  --iasl=IASL              use ACPI compiler IASL [$iasl]"
+echo "                           iasl=false disables the ACPI compiler"
 echo "  --host-cc=CC             use C compiler CC [$host_cc] for code run at"


Stefan