Re: trident noise
That sounds like the problem (more or less), but I don't know how it
could have been turned on by default. I'll give it a try.
Sven LUTHER <email@example.com> writes:
> On Tue, Aug 13, 2002 at 04:01:36PM -0400, Russell Neches wrote:
> > Hey there --
> > I've recently been tinkering with VIA's EPIA motherboard and the
> > various gizmos integrated into VIA's "super southbridge" chip.
> > Basically everything is crammed into this chip:
> > 00:00.0 Host bridge: VIA Technologies, Inc. VT8601 [Apollo ProMedia] (rev 05)
> > 00:01.0 PCI bridge: VIA Technologies, Inc. VT8601 [Apollo ProMedia AGP]
> > 00:11.0 ISA bridge: VIA Technologies, Inc. VT8231 [PCI-to-ISA Bridge] (rev 10)
> > 00:11.1 IDE interface: VIA Technologies, Inc. Bus Master IDE (rev 06)
> > 00:11.2 USB Controller: VIA Technologies, Inc. UHCI USB (rev 1e)
> > 00:11.3 USB Controller: VIA Technologies, Inc. UHCI USB (rev 1e)
> > 00:11.4 Bridge: VIA Technologies, Inc. VT8235 Power Management (rev 10)
> > 00:11.5 Multimedia audio controller: VIA Technologies, Inc. AC97 Audio Controller (rev 40)
> > 00:12.0 Ethernet controller: VIA Technologies, Inc. Ethernet Controller (rev 51)
> > 00:13:0 Kitchen sink: VIA Technologies, Inc. Sink (rev 08) Faucet (rev 11b)
> > 01:00.0 VGA compatible controller: Trident Microsystems CyberBlade/i1 (rev 6a)
> > (all right, 00:13 is fictional)
> > The problem I've been having is something I've not seen much since AGP
> > came around - the sound card chirps and skips when you move a window
> > around. I've tried everything I can think of to reproduce the problem
> > in other ways, but I'm pretty confidant that I've isolated it to X.
> > Playing with DMA mode on the disk, unloading the network driver,
> > blasting the CPU to induce latency and all permutations of such abuse
> > fail to cause the sound card to skip. In fact, it sounds pretty good
> > for inexpensive hardware. However, as soon as X is loaded and a window
> > is perturbed, the sound card goes insane.
> > Now, if I remember my history, PCI video card manufacturers discovered
> > at some point that they could lengthen the little bars produced by
> > WinBench by a few percent if they wrote blindly to the instruction
> > queue on the video card. This didn't cause trouble for most PCI
> > devices, but it caused that obnoxious popping and squeaking from sound
> > cards. The PCI bus would lock up for a few tens of audio cycles -
> > insignificant for filesystem performance, but you will definitely hear
> > (and hate) it. The only way to fix it was to put the code that checks
> > the video instruction queue back into the video driver.
> I am not sure, but what you describe could be the usage of the PCI
> disconnect feature, in which the video card would disconnect from the
> bus until there is space in the instruction queue, while the processor
> keeps resending the data until there is space in the fifo, thus eating
> all the bus bandwith.
> I don't know the trident driver, but from the manpage, maybe you could
> unset the following option :
> Option "PciRetry" "boolean"
> Enable or disable PCI retries. Default: off.
> You see, it seems to default to off, but may get enabled in the config
> file, please check.
> Sven Luther
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