Re: [Qemu-devel] Re: OSS audio debugging

[malc <malc@pulsesoft.com>]

On Mon, 14 Jun 2004, Mike Nordell wrote:

> malc wrote:
>
> > And while im figuring this out you can
> > try experimental SDL output driver(but see caveats):
>
> I've made some quite heavy modifications to your SDL audio patch, and from
> where I stand it now seems to work. It might seem a bit bloated in places,
> and it contains quite a lot of experimental code for tweaking. As the diff
> became larger than the file itself, I attached the file.
>
> I'd appreciate reports from both Win32'ers and *nix land using SDL, to see
> if there are any SDL differences between platforms not handled.

<snip>
>
> DOOM Shareware - this one needs no introduction.
> Crashes, hangs and plays really "choppy" sound.
> The crashes and hangs (depending on moon-phase) seems to be due to
> incomplete detection of self-modifying code. When it does run for more than
> 1 second, the choppy sound I suspect might be, as for many cases here, due
> to timing or incorrect SB16, PIC or DMA emulation. That it also run as in
> molasses (the seconds I got it to run) further strengthen my suspicions of
> timing or PIC - even that it could be a large amount of self-modifying code
> invalidating the TB all the time too. I haven't dug deeper into it.
>

Disabling TB chainging helps running DOOM. As for chopyness, DMA buffer
is very small for OSS setting fragsize,nfrags helps.

>
> Transport Tycoon
> With -cirrus-vga it fails to start with error "Unable to set up SVGA
> display".
> Without cirrus it switches video mode, but then seems to just hang.

You can try UNIVBE, Scitech has a free(both senses) download.

>
> Windows 2000 sp4. Works, except every sound buffer sent (from host to
> emulator, I suspect) seems to play twice. Even the "tick" sound when moving
> from one folder to another in the Explorer is "echoed". CPU load is not high
> during audio playback, why I suspect
> timing, PIC, DMA or SB16 emulation problems. Other, larger, waveform
> playback sounds horrible due to this echo/reverb effect - and the fact it
> seems to not even play at the full speed it should, seems to suggest PIC
> problems (interrupt not delivered to guest?).
> With my slirp DHCP networking patch, and addition of the NE2000 ASIC writeb
> (neither yet committed it seems) it even got an IP from slirp DHCP on every
> boot. Never been able to access anything but the host machine itself though,
> and then only with a ICMP ping (which slirp rewrites as a UDP ping). DNS
> queries do leave host machine and passes through a gateway, and returns, but
> never seems to reach the guest OS. TCP socket has never been opened by QEMU
> despite attempts.
>
>
> Windows 98.
> Only tested with -enable-audio -cirrusvga -pci -nics 0.
> Claims the SB16 device is not functional. The usual suspects. Nothing else
> tested.

Default Win98 sound driver does not work indeed, though installing WDM
driver from W2K(as per VMWare instructions) helped a lot. Sounds MUCH
better than in W2K anyway.

>
>
> Even with these problems, I'd say QEMU is starting to become possibly the
> best PC emulator there is. As a sidenote I can mention I tested one of the
> DOS programs under VMWare. Yep, VMWare crashed allright. ;-P
>
>
> /Mike
>

-- 
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