From: Cao jin <caoj.fnst@cn.fujitsu.com>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Netdev <netdev@vger.kernel.org>,
"Izumi, Taku/泉 拓" <izumi.taku@jp.fujitsu.com>,
intel-wired-lan <intel-wired-lan@lists.osuosl.org>
Subject: Re: [Intel-wired-lan] [PATCH] igb: drop field "tail" of struct igb_ring
Date: Tue, 8 Nov 2016 14:07:58 +0800 [thread overview]
Message-ID: <58216BBE.5000108@cn.fujitsu.com> (raw)
In-Reply-To: <CAKgT0UcZiJJbb+-vCkhL=A2X9CB+ekp8-CnTZznEB+NBMYALFg@mail.gmail.com>
On 11/08/2016 12:12 PM, Alexander Duyck wrote:
>
>
> On Monday, November 7, 2016, Cao jin <caoj.fnst@cn.fujitsu.com
> <mailto:caoj.fnst@cn.fujitsu.com>> wrote:
>
>
>
> We removed head because it isn't really accessed very often, it is only
> really used for when the ring is configured. Tail is accessed every
> time we add a descriptor to a ring. The pointer chasing from ring to
> netdev to adapter to hw is expensive. That is one of the rasons why
> we cache the pointer to the tail register.
I see. I can submit the patch as you suggested.
>
> Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
> ---
> drivers/net/ethernet/intel/igb/igb.h | 1 -
> drivers/net/ethernet/intel/igb/igb_main.c | 16
> +++++++++-------
>
> hw->hw_addr could be alterred to NULL(in igb_rd32), this is why
> writel oops the kernel, you give a fine solution.
>
> But from the oops message, we can find, register reading returns all
> F's, I also have a question want to consult: when igb device is
> reset, would reading register(no matter config space or non-PCIe
> configuration registers) during reset returns all F's? (I guess this
> is the core of my issue)
>
>
> An all F's value means the read failed. The device is likely off of the
> bus and the hw_addr may not have been repopulated after the reset.
>
> You might want to check the mailing list as I thought someone had
> submitted a patch recently for one of the drivers to repopulate hw_addr
> after a reset.
>
I guess you are saying this one:
http://patchwork.ozlabs.org/patch/689592/
Seems they have a similar issue with me.
--
Yours Sincerely,
Cao jin
prev parent reply other threads:[~2016-11-08 6:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-07 12:44 [PATCH] igb: drop field "tail" of struct igb_ring Cao jin
2016-11-07 18:49 ` [Intel-wired-lan] " Alexander Duyck
2016-11-08 2:50 ` Cao jin
[not found] ` <CAKgT0UcZiJJbb+-vCkhL=A2X9CB+ekp8-CnTZznEB+NBMYALFg@mail.gmail.com>
2016-11-08 6:07 ` Cao jin [this message]
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