Re: [PATCH] PCI: MSI: Only use the generic MSI layer when domain is hierarchical

[Marc Zyngier <marc.zyngier@arm.com>]

On Thu, 3 Dec 2015 18:27:59 -0600
Bjorn Helgaas <helgaas@kernel.org> wrote:

> On Mon, Nov 30, 2015 at 10:25:34AM +0000, Phil Edworthy wrote:
> > Cc'd linux-pci ml
> > 
> > On 23 November 2015 14:27, Marc Zyngier wrote:
> > 
> > Since d8a1cb757550 ("PCI/MSI: Let pci_msi_get_domain use struct
> > device::msi_domain"), we use the MSI domain associated to the PCI device.
> > 
> > But finding a MSI domain doesn't mean that the domain is implemented
> > using the generic MSI domain API, and a number of MSI controllers
> > are still using the arch_setup_msi_irq/arch_teardown_msi_irqs.
> > 
> > In order to avoid a firework on these systems, check that the domain
> > we just obtained is hierarchical. If not, don't use the generic MSI
> > stuff and stick with the old one. Not pretty, but reliable.
> > 
> > Another insentive to rework those drivers and phase out this API.
> > 
> > Reported-by: Phil Edworthy <phil.edworthy@renesas.com>
> > Tested-by: Phil Edworthy <phil.edworthy@renesas.com>
> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> 
> Thanks, I applied this with Thomas' ack to pci/msi for v4.5.
> 
> It looks like d8a1cb757550 appeared in v4.3.  Is this a fix for that
> commit?  Does this need to be backported via a stable tag?

Hi Bjorn,

I think this really deserves to be queued as an immediate fix for 4.4
rather than 4.5, as some systems in mainline are affected by this bug:

http://www.spinics.net/lists/arm-kernel/msg465792.html

It would also deserve a stable tag for 4.3.

Thanks,

	M.
-- 
Without deviation from the norm, progress is not possible.