Re: [Qemu-devel] [PATCH] rtl8139: honor RxOverflow flag in can_receive method

["Fernando Luis Vázquez Cao" <fernando@oss.ntt.co.jp>]

On 02/02/2012 07:11 AM, Anthony Liguori wrote:
> On 01/29/2012 08:17 PM, Fernando Luis Vázquez Cao wrote:
>> Some drivers (Linux' 8139too among them) rely on the NIC injecting an 
>> interrupt
>> in the event of a receive buffer overflow and, accordingly, set the 
>> RxOverflow
>> bit in the interrupt mask. Unfortunately rtl8139's can_receive method 
>> ignores
>> the RxOverflow flag, which may lead to a situation where rtl8139 
>> stops receiving
>> packets (can_receive returns 0) when the receive buffer becomes full.
>>
>> If the driver eventually read from the receive buffer or reset the 
>> card the
>> emulator could recover from this situation. However some 
>> implementations only
>> do this upon receiving an interrupt with either RxOK or RxOverflow 
>> set in the
>> ISR; interrupt that will never come because QEMU's flow control 
>> mechanisms would
>> prevent rtl8139 from receiving any packet.
>>
>> Letting packets go through when the overflow interrupt is enabled 
>> makes the
>> QEMU emulator compliant to the spec and solves the problem.
>>
>> This patch should fix a relatively common (in our experience) network 
>> stall
>> observed when running enterprise distros with rtl8139 as the NIC; in 
>> some cases
>> the 8139too device driver gets loaded and when under heavy load the 
>> network
>> eventually stops working.
>>
>> Reported-by: Hayato Kakuta<kakuta.hayato@oss.ntt.co.jp>
>> Tested-by: Hayato Kakuta<kakuta.hayato@oss.ntt.co.jp>
>> Signed-off-by: Fernando Luis Vazquez Cao<fernando@oss.ntt.co.jp>
>
> Applied.  Thanks.

Hi Anthony,

It seems that this patch did not make it into the git tree.
Did you find any merge conflicts?

Thanks,
Fernando