Re: [B2-devel] problems caused(?) by recent patches

[Alexei S. <ale...@gm...>]

I've reverted the SDL audio patch.

On Thu, Jan 14, 2010 at 3:06 PM, Ronald P. Regensburg
<ron...@xs...> wrote:
> In answer to the comments by Charles Srstka:
>
> About the precise timer patch:
> The crash with the precise timer crash was not limited to PPC
> machines. I noticed it myself on a PPC machine first while it did not
> happen on my Intel machine. However, within 6 days after posting my
> 18-10-2009 build I got in the SheepShaver forum four reports of the
> crash, each at the very same moment in the startup process, one on a
> PPC machine and three on a Intel machine. The 25-10-2009 build
> (without the precise timer patch) solved the crash for myself on my
> PPC machine as well as for the other reported PPC machine and for two
> out of the three reported Intel machines. On the third reported Intel
> machine the 25-10-2009 crashed with a SIGSEGV. That crash was resolved
> by enabling "Ignore Illegal Memory Accesses" (ignoresegv true). Later,
> there were a few more reports of SIGSEGV crashes on Intel machines
> with the 25-10-2009 build that could be solved this way. So far, I got
> one report of the 25-10-2009 build crashing with a SIGSEGV in Leopard
> on a PPC machine, not yet solved nor understood.
>
> About the sdl-audio patch:
> Probably best to simply remove the patch. In the original
> pre-19-02-2009 BasiliskII/src/SDL/audio_sdl.cpp file the value for
> audio_spec.samples is set to 4096, well within the recommended range.
>
> Ronald.
>
>
> Op 14 jan 2010, om 17:11 heeft Charles Srstka het volgende geschreven:
>
>> On Jan 14, 2010, at 7:18 AM, Ronald P. Regensburg wrote:
>>
>>>
>>> In Emaculation.com forums, Alexei Svitkine asked me to mail to this
>>> list about patches I needed to revert before building SheepShaver
>>> (and
>>> BasiliskII) for Mac OS X in order to avoid problems.
>>>
>>>
>>> The problems with the "precise timer patch" were discussed in the
>>> basilisk-devel list between October 23 and October 28. Those problems
>>> were the reason for me to make the 25-10-2009 build for
>>> Emaculation.com within days after the 18-10-2009 build.
>>>
>>> In my last October 25 message to the basilisk-devel list I told which
>>> files I used for the 25-10-2009 build to omit the "precise timer
>>> patch" and the "sdl-audio patch".
>>>
>>> The "sdl-audio patch" apparently made sound for most users worse
>>> rather than better. Users of both BasiliskII and SheepShaver builds
>>> created after that patch was added, complained about the problems for
>>> months and reported considerable improvement when I posted builds of
>>> both without the patch. That happened before I joined this mailing
>>> list. The problems were sound delays, stuttering, even skipping of
>>> sounds. The problem was more serious in BasiliskII than in
>>> SheepShaver.
>>>
>>> I do not know whether these patches actually cause the problems or
>>> just make bugs in other parts of the code apparent.
>>
>> The crash with the precise timer patch was mostly limited to running
>> the app on PPC machines if I remember correctly, wasn’t it? Since
>> SheepShaver runs completely different code paths on PPC and Intel,
>> with the PPC version running native code and the Intel using
>> emulation, I can see how the change could have caused problems with
>> one that would not have come up on the other. The best solution in
>> this case may be to enable the precise timer patch only when
>> building for Intel.
>>
>> The SDL audio patch, on the other hand, is simply ill-advised in my
>> opinion. The docs for SDL recommend using a value between 512 and
>> 8192 for the ‘samples’ field of an SDL_AudioSpec. The patch in the
>> SheepShaver source sets it to 16384. The result is laggy audio. I
>> think the patch was made to reduce the demands on processing power
>> for older machines, but for those with modern hardware it seems to
>> cause more problems than it solves.
>>
>> Charles
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>
>
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