RE: [PATCH RFC 7/7] irqchip: [Example] dummy wired interrupt/MSI bridge driver

[Gabriele Paoloni]

> -----Original Message-----
> From: Marc Zyngier [mailto:marc.zyngier@xxxxxxx]
> Sent: Thursday, November 05, 2015 9:36 AM
> To: Gabriele Paoloni; majun (F); Thomas Gleixner; Jiang Liu; Jason
> Cooper
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH RFC 7/7] irqchip: [Example] dummy wired
> interrupt/MSI bridge driver
> 
> On 05/11/15 08:25, Gabriele Paoloni wrote:
> > Hi Marc
> >
> >> -----Original Message-----
> >> From: linux-pci-owner@xxxxxxxxxxxxxxx [mailto:linux-pci-
> owner@xxxxxxxxxxxxxxx]
> >> On Behalf Of Marc Zyngier
> >> Sent: 04 November 2015 09:04
> >> To: majun (F); Thomas Gleixner; Jiang Liu; Jason Cooper
> >> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> linux-
> >> kernel@xxxxxxxxxxxxxxx
> >> Subject: Re: [PATCH RFC 7/7] irqchip: [Example] dummy wired
> interrupt/MSI
> >> bridge driver
> >>
> >> On 04/11/15 08:00, majun (F) wrote:
> 
> [...]
> 
> >>> I think,for a interrupt controller, msichip driver initialization
> maybe is
> >> too late
> >>> for some devices which connect to this irqchip if we use
> >> module_platform_driver.
> >>
> >> That's a consequence of this design. This is why I insisted on the
> fact
> >> that this is currently avoided by using deferred probe in drivers,
> and
> >
> > Mmm using te deferred probe would mean to rework all the drivers of
> the
> > potential devices connected to mbi-gen...would that be
> sustainable/acceptable?
> 
> I'm tempted to reply "Not my problem". Or rather, not a problem I'm
> trying to solve right now (or any time soon).
> 
> I'm pretty sure that sprinkling -EPROBE_DEFER on all possible drivers
> will result in a resounding NAK, which is is why I suggested that
> someone with a vested interest dedicates some quality time helping
> those
> who are trying to solve this issue for good.

Yes you're right, makes perfect sense

> 
> >> that it should be solved by having a probe order. Either way, this
> is
> >> not something that we can solve at that level (see the multiple
> proposal
> >> for this on the various lists).
> >
> > Could you point me to the relevant discussions for this...?
> 
> Google is, as always, your dearest friend. But here you go:
> 
> - LWN has some quality coverage of the KS discussions (assuming you're
> a
> subscriber, otherwise you'll have to wait for another week):
> http://lwn.net/Articles/662820/
> 
> - There is also Tomeu Vizoso's series, which itself builds upon other
> previous attempts at solving this: https://lwn.net/Articles/658690/
> 

Great, many thanks for pointing them out.

I'll look into these.

Thanks again

Gab

> Thanks,
> 
> 	M.
> --
> Jazz is not dead. It just smells funny...