[PATCH] yenta: irq-routing for TI bridges...again

[Russell King]

On Tue, Mar 09, 2004 at 01:15:33PM -0500, Pavel Roskin wrote:
> On Fri, 5 Mar 2004, Daniel Ritz wrote:
> > > mfunc_old is assigned 0 in the beginning of ti12xx_override().  It's never
> > > changed.  Now let's find the third (i.e. the last) "changing mfunc to".
> > > The driver sets mfunc it has printed (00001002), calls yenta_probe_irq()
> > > and then silently restores mfunc_old, which is still 0.  My card needs 2
> > > in that register.  All that needs to be unset is 0x1000.
> >
> > you are right. fixed in the incremental patch attached..
> 
> I don't see any interest to your efforts from anybody who can apply your
> patches.  I wonder if we are wasting time.

Although I haven't been making many comments, I have been keeping an
eye on this; I'm fairly busy at the moment which doesn't help.

I recently directed a PARISC guy to these patches - he has a similar
problem on a PARISC laptop, so fixing it in some way which makes him
happy as well is advantageous if possible.

> > hmmm...it could hurt. remember the comment in the disabled INTA routing
> > code about falling back from all-serial causes hangs on some setups...
> > there can be setups with uninitialised chips where all-serial (default)
> > is actually right, just mfunc is wrong.
> 
> Please be exact.  I think you mean this:
> 
>         /*
>          * If ISA interrupts don't work, then fall back to routing card
>          * interrupts to the PCI interrupt of the socket.
>          *
>          * Tweaking this when we are using serial PCI IRQs causes hangs
>          *   --rmk
>          */
> 
> I think you are missing an important fact here.  The comment precedes an
> old patch that didn't check if irqmux (a.k.a mfunc) was 0.

Indeed - I had a report where changing the configuration from serial
PCI IRQs caused the whole machine to hang solid.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core