Re: lost interrupts when running sabrelite images (v4.15+) in qemu

[Guenter Roeck]

On 03/03/2018 12:48 PM, Guenter Roeck wrote:
> On 03/03/2018 11:07 AM, Troy Kisky wrote:
> > On 3/3/2018 8:32 AM, Guenter Roeck wrote:
> > > Hi,
> > >
> > > since v4.15, I get the following runtime warning when running sabrelite images
> > > in qemu.
> > >
> > > irq 65: nobody cared (try booting with the "irqpoll" option)
> > > ...
> > > handlers:
> > > [<26292474>] fec_pps_interrupt
> > > Disabling IRQ #65
> > > fec 2188000.ethernet (unnamed net_device) (uninitialized): MDIO read timeout
> > >
> > > Bisect points to commit 4ad1ceec05e491 ("net: fec: Let fec_ptp have its
> > > own interrupt routine"). Analysis shows that platform_irq_count()
> > > returns 2, which is reduced to 1 by fec_enet_get_irq_cnt().
> > > If I let fec_enet_get_irq_cnt() return 2, the problem is gone.
> > > Reverting commit 4ad1ceec05e491 also fixes the problem.
> > >
> > > Bisect log is attached.
> >
> > Sounds like you found a bug with qemu. I just booted sabrelite over nfs fine.
> > My interrupts look like this.
> >
> >
> > Â 64:ÂÂÂÂÂ 98767ÂÂÂÂÂÂÂÂÂ 0ÂÂÂÂÂÂÂÂÂ 0ÂÂÂÂÂÂÂÂÂ 0ÂÂÂÂ GIC-0 150 LevelÂÂÂÂ 2188000.ethernet
> > Â 65:ÂÂÂÂÂÂÂÂÂ 0ÂÂÂÂÂÂÂÂÂ 0ÂÂÂÂÂÂÂÂÂ 0ÂÂÂÂÂÂÂÂÂ 0ÂÂÂÂ GIC-0 151 LevelÂÂÂÂ 2188000.ethernet
> > ___________
> > Irq 65 is only for ptp interrrupts now. If qemu is signaling an tx/rx frame interrupt on 65,
> > then qemu is wrong. Of course, I've never used qemu so feel free to ignore me if I make no sense.
>
> Thanks for checking with real hardware.
>
> This is what I see (with your patch reverted):
>
>  Â64:ÂÂÂÂÂÂÂÂÂ 0ÂÂÂÂ GIC-0 150 LevelÂÂÂÂ 2188000.ethernet
>  Â65:ÂÂÂÂÂÂÂÂ 64ÂÂÂÂ GIC-0 151 LevelÂÂÂÂ 2188000.ethernet
>
> Looking into the qemu source, I see:
>
> #define FSL_IMX6_ENET_MAC_1588_IRQ 118
> #define FSL_IMX6_ENET_MAC_IRQ 119
>
> FSL_IMX6_ENET_MAC_IRQ is then connected to fec interrupt index 0, and FSL_IMX6_ENET_MAC_1588_IRQ
> is connected to fec interrupt index 1.
>
> This may suggest that the defines are reversed. I'll see what happens if I swap them.

Confirmed. If I swap the above defines, everything works fine. At the same time,
the modified qemu works with older kernels.

Thanks a lot for the hint, and sorry for the noise.

Guenter