Re: [Qemu-devel] [PATCH] i.MX: Fix FEC/ENET receive funtions

[Jean-Christophe Dubois]

Le 2018-01-12 18:08, Peter Maydell a écrit :
> On 10 January 2018 at 20:38, Jean-Christophe Dubois 
> <address@hidden> wrote:
> > The actual imx_eth_enable_rx() function is buggy.
> >
> > It updates s->regs[ENET_RDAR] after calling 
> > qemu_flush_queued_packets().
> >
> > qemu_flush_queued_packets() is going to call imx_XXX_receive() which 
> > itself
> > is going to call imx_eth_enable_rx().
> >
> > By updating s->regs[ENET_RDAR] after calling 
> > qemu_flush_queued_packets()
> > we end up updating the register with an outdated value which might
> > lead to disabling the receive function in the i.MX FEC/ENET device.
> >
> > This patch change the place where the register update is done so that 
> > the
> > register value stays up to date and the receive function can keep
> > running.
> >
> > Reported-by: Fyleo <address@hidden>
> > Tested-by: Fyleo <address@hidden>
> > Signed-off-by: Jean-Christophe Dubois <address@hidden>
>
> Could you have a look at current QEMU master, please? I think that
> commit b2b012afdd9c has probably fixed this bug. (At any rate it
> has changed that code so that your patch won't apply.)

It seems the patch (imx_fec: Refactor imx_eth_enable_rx()) only renamed 
a variable (from tmp to rx_ring_full) without changing the logic. So I 
don't expect the bug to be fixed in mainline.

I'll rebase and resubmit my patch.

JC


> thanks
> -- PMM