Re: DMA conflicts with soundcard for ide driver via82cxxx

From: Vojtech Pavlik (vojtech@suse.cz)
Date: Tue Jan 01 2002 - 17:20:22 EST


On Tue, Jan 01, 2002 at 11:03:52PM +0100, Edward Stempel wrote:
> In my BIOS-setup there is an option "PCI latency" which defaults to
> 32. First I changed it to 128. That worked perfect. Later I have decreased
> it to 64, 48 and 40. But 40 still gave some problems (a little bit
> distortion of my sound). After that I tried 44, but the disk was to slow
> with this setting (30 MB/s instead of 40 MB/s). So now I have a PCI
> latency of 48. The strange thing is that it seems not to work
> directly. After the system boot when I do hdparm -t, I get about 5
> MB/s. But then when I switch using_dma off and on again using hdparm, I
> get the full 40 MB/s and no distortion of my es1371. Any ideas what might
> cause this?

You'd have to tell me all other settings in your setup first so I can
guess the cause. What options do you use? Is DMA enabled automatically?
Etc, etc ...

>
> Regards,
>
> Edward
>
>
>
>
> ---------- Forwarded message ----------
> Date: Tue, 1 Jan 2002 18:14:41 +0100
> From: Vojtech Pavlik <vojtech@suse.cz>
> To: Edward Stempel <eazstempel@cal009001.student.utwente.nl>
> Cc: linux-kernel mailinglist <linux-kernel@vger.kernel.org>
> Subject: Re: DMA conflicts with soundcard for ide driver via82cxxx
>
> On Fri, Dec 28, 2001 at 05:10:43PM +0100, Edward Stempel wrote:
>
> > Excellent! That solved my problem.
>
> What exactly did you have to change? It might be worth to include the
> changing of the latency setting in the kernel.
>
> >
> > Thankx
> >
> > Edward
> >
> >
> >
> >
> > Date: Fri, 28 Dec 2001 10:15:05 +0100
> > From: Vojtech Pavlik <vojtech@suse.cz>
> > To: Edward Stempel <eazstempel@cal009001.student.utwente.nl>
> > Cc: linux-kernel mailinglist <linux-kernel@vger.kernel.org>
> > Subject: Re: DMA conflicts with soundcard for ide driver via82cxxx
> >
> > On Fri, Dec 28, 2001 at 03:32:34AM +0100, Edward Stempel wrote:
> >
> > > I have an Asus a7v266 mother board and an Ensoniq sound card in it.
> > > The ide chipset is a VIA VT8233 that is capable of UDMA100. So I built a
> > > kernel with the es1371 sound driver and the via82cxxx ide driver
> > > configured in it. Actually I tried the kernel 2.4.17 first, and the latest
> > > I tried is 4.5.1 with the latest patch (patch-2.5.2-pre3) applied to it.
> > > I also tried the kernel 2.5.1 with Vojtech patch (via-3.33.diff from
> > > his email dated 2001-12-23 23:20:48) applied to it, with the same
> > > (negative) results.
> > >
> > > The good thing is that hdparm reports appr. 40 MB/sec when using DMA and
> > > about 6 MB/sec when not using DMA.
> > > Unfortunately using DMA for ide results in some ugly distortion of the
> > > sound from my soundcard whenever some IO to the disk is done. :((
> > >
> > > I have assigned different interrupts to the PCI-cards (ide is
> > > on-board) and I even changed the sound card's PCI slot, so it shared
> > > its interrupt with another device (acpi instead of USB). It did not solve
> > > the problem. Because the problem only occurs when switching on using_dma
> > > on the ide driver, I think it is a DMA problem with the ide driver. It may
> > > be the es1371 driver as well off course, but I suspect it is the ide
> > > driver (or chipset).
> > >
> > > Reading the list archive from linux-kernel, I discovered there have been
> > > more problems with DMA using this chipset, but I did not find anyone
> > > having the same problem as I have now.
> > >
> > > Has someone also dealt with these problems, or can someone help me
> > > solving this problem? Please help!
> > >
> > > Below are some outputs using kernel 5.1 with patch-2.5.2-pre3.
> >
> > You may try changing the PCI latency settings on either the IDE
> > controller or the sound card. Other than that, I don't know how to help.
> >
> > --
> > Vojtech Pavlik
> > SuSE Labs
>
> --
> Vojtech Pavlik
> SuSE Labs

-- 
Vojtech Pavlik
SuSE Labs
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