Subject: Re: [net 1/3] i40e: fix un-necessary Tx hangs

From: Jesse Brandeburg <[email-masked]>
Date: Tue, 6 Jan 2015 09:04:40 -0800

On Tue, 6 Jan 2015 00:44:22 -0800
Jeff Kirsher <[email-masked]> wrote:

> From: Jesse Brandeburg <[email-masked]>
> 
> When the driver was polling with interrupts disabled the hardware
> will occasionally not write back descriptors.  This patch causes
> the driver to detect this situation and force an interrupt to
> fire which will flush the stuck descriptor.  Does not conflict
> with NAPI because if we are already polling the napi_schedule is
> ignored.  Additionally the extra interrupts are rate limited, so
> don't cause a burden to the CPU.

Dave, sorry to do this but we discovered a bug in this patch (where
this patch impacts performance) and didn't interrupt Jeff before he sent
it (my mistake) I will prep a v2 for Jeff.

Please do not apply.