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

[Guenter Roeck]

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.
>
>
>   64:      98767          0          0          0     GIC-0 150 Level     2188000.ethernet
>   65:          0          0          0          0     GIC-0 151 Level     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):

 64:          0     GIC-0 150 Level     2188000.ethernet
 65:         64     GIC-0 151 Level     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.

Thanks,
Guenter