Hi Zhang,

If you look at the source of interrupt handlers in both the igb_uio and 
uio_pci_generic drivers (look for irqreturn_t type), you will see they can 
disable interrupts immediately after receipt of one.
It's up to the user to make sure they're re-enabled. Also please compare with 
code in i40e_ethdev.c, which still does this correctly - there's an explicit 
rte_intr_enable(dev->intr_handle) call at the end of 
Probably a cleaner approach would be to leave them disabled as is, but only 
enable them for a once-off receipt when sending an AdminQ message, maybe that 
was the assumption here. However I've added some tracing to 
igbuio_pci_irqcontrol() and I'm sure this isn't happening on my system. 
(nothing is enabling those interrupts post device init). Looks like code path 
might be different with the newest igb_uio driver and MSI enabled, but the 
current code will still not work for all cases (like with uio_pci_generic).
There can also be cases when you have and older igb_uio driver which disables 
interrupts in all cases and running it with with a new DPDK. (vendor provided 
compiled driver) I think for full compatibility we need to keep re-enabling 
those interrupts.


-----Original Message-----
From: Zhang, Qi Z 
Sent: Wednesday, March 28, 2018 4:37 AM
To: Jankowski, Konrad <konrad.jankow...@intel.com>; Dai, Wei 
<wei....@intel.com>; Xing, Beilei <beilei.x...@intel.com>; Wu, Jingjing 
<jingjing...@intel.com>; dev@dpdk.org
Subject: RE: [PATCH] net/i40evf: regression fix - reenable interrupts in handler

Hi Jankowski:

> -----Original Message-----
> From: Jankowski, KonradX
> Sent: Thursday, February 15, 2018 2:33 AM
> To: Dai, Wei <wei....@intel.com>; Xing, Beilei 
> <beilei.x...@intel.com>; Zhang, Qi Z <qi.z.zh...@intel.com>; Wu, 
> Jingjing <jingjing...@intel.com>; dev@dpdk.org
> Cc: Jankowski, KonradX <konradx.jankow...@intel.com>
> Subject: [PATCH] net/i40evf: regression fix - reenable interrupts in 
> handler
> Commit 66b8304f removed the rte_intr_enable() call from
> i40evf_dev_interrupt_handler() as a "bonus". On one of my systems this 
> causes the AdminQ messages to stop beeing delivered to the VF. This 
> results in unability to initialize and use the port. With this patch it works 
> again.
> System in question:
> Wind River OVP6 running kernel 3.10.58-ovp-rt58-WR6.0.0.13_preempt-rt
> Signed-off-by: Konrad Jankowski <konrad.jankow...@intel.com>
> ---
>  drivers/net/i40e/i40e_ethdev_vf.c | 1 +
>  1 file changed, 1 insertion(+)
> diff --git a/drivers/net/i40e/i40e_ethdev_vf.c
> b/drivers/net/i40e/i40e_ethdev_vf.c
> index fd003fe..b927a35 100644
> --- a/drivers/net/i40e/i40e_ethdev_vf.c
> +++ b/drivers/net/i40e/i40e_ethdev_vf.c
> @@ -1404,6 +1404,7 @@ i40evf_dev_interrupt_handler(void *param)
>  done:
>       i40evf_enable_irq0(hw);
> +     rte_intr_enable(dev->intr_handle);'

Would you explain more about why the patch fix the issue?
Usually we will not accept a fix just because it work but not understand the 
root cause.


>  }
>  static int
> --
> 2.5.5

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