Re: [PATCH update] firewire: fw-ohci: work around generation bug in TI controllers (fix AV/C and more)

From: Jarod Wilson
Date: Thu Apr 17 2008 - 22:51:32 EST


On Thursday 17 April 2008 06:47:16 pm Stefan Richter wrote:
> Jarod Wilson wrote:
> > On Saturday 12 April 2008 04:31:25 pm Stefan Richter wrote:
> >> + ohci->bus_reset_packet_quirk = dev->vendor == PCI_VENDOR_ID_TI;
> >> +
> >
> > I have a few cards with PCI_VENDOR_ID_CREATIVE with a TI TSB41AB2 chip on
> > 'em (SoundBlaster Audigy w/FireWire port). I've not had any issues on any
> > of the cards I've got, but do we want to add them to the work-around list
> > just to be safe?
>
> No, we don't need to. TSB41AB2 is only a PHY, not a link layer
> controller. While the PHYs (the combination of PHYs which are present
> on the bus) influence the conditions under which the bug can happen, the
> cause for the bug is in the link layer controller alone.
>
> So unless Creative used a TI design in their link layer controller or
> otherwise managed to implement this same quirk as TI (Agere, NEC, and
> VIA didn't according to my tests so far), the presence of TSB41AB2 on a
> card does not make it necessary to activate the quirk workaround.

Ah, I'll have to take a closer look at these cards and see if I can figure out
what drives the link layer... But barring the discovery of another TI chip,
I'm assuming an attempt to reproduce the generation issue will be fruitless.

Well, based on the positive results we've seen thus far with TI controllers
and this patch in Fedora kernels:

Signed-off-by: Jarod Wilson <jwilson@xxxxxxxxxx>

--
Jarod Wilson
jwilson@xxxxxxxxxx
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