[ATA] and re(4) stability issues
pyunyh at gmail.com
Wed Dec 10 18:49:43 PST 2008
On Wed, Dec 10, 2008 at 03:08:24PM +0100, Victor Balada Diaz wrote:
> On Wed, Dec 10, 2008 at 09:07:19PM +0900, Pyun YongHyeon wrote:
> > > > > > It seems that your controller supports MSI so you can set a tunable
> > > > > > hw.re.msi_disable to 0 to enable MSI. With MSI you can remove
> > > > > > interrupt sharing(e.g. add hw.re.msi_disable="0" to
> > > > > > /boot/loader.conf file.) However there were several issues on re(4)
> > > > > > w.r.t MSI so it was off by default.
> > > > >
> > > > > This is undocumented and with sysctl -a i can't find the tunable. Is this
> > > > > a HEAD feature or it's also in 7.1 -BETA2? Should i add
> > > >
> > > > Yeah it's an undocmented feature. But most drivers written by me
> > > > have similar kobs. Both HEAD and stable/7 including 7.1 BETA2 have
> > > > the tunable.
> > >
> > > I think it could be great if you could document it or at least
> > > show it by default when you do sysctl -ad with a small description.
> > >
> > If MSI worked as expected I would have documented it as I did
> > in msk(4)/nfe(4)/ale(4)/age(4)/jme(4) etc.
> > Using MSI on RealTek does not seem to stable. I tried hard to fix
> > that but some users still reported watchdog timeouts. Working
> > without documentation and hardware also made it hard to complete
> > the work. This was the main reason why MSI was disabled on re(4).
> What do you think about adding a note in the man page telling that
> it's experimental and in some cases it could improve the situation
> but in others it will give errors?
Based on the your testing I have idea how to mitigate the missing
Tx completion interrupt. If all goes well re(4) could reliably take
advantage of MSI on RealTek controllers. If that miserably fail I
would do as you suggested.
> > I think re(4) in HEAD needs more testing. As you might know RealTek
> > produced too many chipsets. :-(
> Ok, i'll use the backported driver as it works better for me :-)
> If i can help you testing any patches i'm more than welcome to do it.
> Thanks a lot for your help Pyun YongHyeon.
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