Re: [Qemu-devel] [RFC PATCH v1 2/2] e1000: adjust initial autoneg timing (for piix/osx)

[Paolo Bonzini <pbonzini@redhat.com>]

Il 30/06/2014 19:55, Michael S. Tsirkin ha scritto:
> 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 <somlo@cmu.edu>
>> ---
>>
>> 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.

It can be turned into a property though.

Paolo