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Re: [Qemu-devel] [RFC PATCH v1 2/2] e1000: adjust initial autoneg timing
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [RFC PATCH v1 2/2] e1000: adjust initial autoneg timing (for piix/osx) |
Date: |
Mon, 30 Jun 2014 20:55:54 +0300 |
On Mon, Jun 30, 2014 at 12:55:50PM -0400, Gabriel L. Somlo wrote:
> When running on PIIX (as opposed to q35), the stock OS X e1000
> driver (AppleIntel8254XEthernet.kext) takes longer to load and
> activete, and will "miss" the link status change interrupt
> injected when the emulated "hardware" autonegotiation completes
> (see commit 39bb8ee737595e9b264d075dfcd7d86f4d3f1133).
>
> This patch extends the delay of the autonetotiation timer set up
> during set_phy_ctrl() to a value just large enough to work with
> the OS X driver.
>
> Signed-off-by: Gabriel Somlo <address@hidden>
> ---
>
> So, the loading OS X driver must take longer between its last
> write to the PHY_CTRL register and the time it starts looking
> for LSC interrupts, because at delay==500 it obviously misses
> the relevant interrupt. Making this 5500 (actually anything
> larger than 5300, but there's a bit of variation across OS X
> versions, so I rounded up a bit) has the timer fire after
> enough time has passed that the driver knows what to do when
> the interrupt from the network card fires...
>
> Thanks,
> Gabriel
>
> hw/net/e1000.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/net/e1000.c b/hw/net/e1000.c
> index 2376910..2300477 100644
> --- a/hw/net/e1000.c
> +++ b/hw/net/e1000.c
> @@ -209,7 +209,7 @@ set_phy_ctrl(E1000State *s, int index, uint16_t val)
> e1000_link_down(s);
> DBGOUT(PHY, "Start link auto negotiation\n");
> timer_mod(s->autoneg_timer,
> - qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 500);
> + qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 5500);
> }
> }
Besides being a bit hacky, it actually has a decent chance
to delay boot for guests. 500ms is probably the max we
can reasonably tolerate, even that is a bit high.
> --
> 1.9.3