Re: [PATCH] PCI: controller: dwc: Make PCI_IMX6 depend on PCIEPORTBUS

[Lucas Stach]

Am Donnerstag, den 06.12.2018, 09:45 -0600 schrieb Robert Hancock:
> On 2018-12-06 2:10 a.m., Baruch Siach wrote:
> > Hi Andrey,
> > 
> > Adding Robert Hancock who reported[1] on a PCIe MSI issue with i.MX6.
> > 
> > Andrey Smirnov writes:
> > 
> > > Building a kernel with CONFIG_PCI_IMX6=y, but CONFIG_PCIEPORTBUS=n
> > > produces a system where built-in PCIE bridge (16c3:abcd) isn't bound
> > > to pcieport driver. This, in turn, results in a PCIE bus that is
> > > capable of enumerating attached PCIE device, but lacks functional
> > > interrupt support.
> > 
> > Robert, does that fix your issue?
> 
> Unfortunately, no.. in fact the situation on my setup is even worse with
> CONFIG_PCIEPORTBUS enabled: Not only does MSI still not function, but
> now INTx interrupts are somehow broken as well - no interrupts are
> received. The IRQ information shown in /proc/interrupts is correct, but
> the count remains stubbornly at 0.

That's expected. The port services will use an MSI IRQ when available
and due to a design issue with the DWC PCIe it will not forward any
legacy IRQs if any MSI is in use. If any of the PCIe devices in your
system are unable to work with MSI IRQs, you must boot with "nomsi" on
the kernel command line set.

Regards,
Lucas