From: Wei Yang <weiyang@linux.vnet.ibm.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: "'Eric Dumazet'" <eric.dumazet@gmail.com>,
David Miller <davem@davemloft.net>,
"weiyang@linux.vnet.ibm.com" <weiyang@linux.vnet.ibm.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"gideonn@mellanox.com" <gideonn@mellanox.com>,
"edumazet@google.com" <edumazet@google.com>,
"amirv@mellanox.com" <amirv@mellanox.com>
Subject: Re: [PATCH net] net/mlx4_en: correct the endianness of doorbell_qpn on big endian platform
Date: Mon, 8 Dec 2014 22:42:37 +0800 [thread overview]
Message-ID: <20141208144237.GB8382@richard> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1CA04A51@AcuExch.aculab.com>
On Mon, Dec 08, 2014 at 10:00:19AM +0000, David Laight wrote:
>From: Eric Dumazet
>> On Fri, 2014-12-05 at 21:31 -0800, David Miller wrote:
>>
>> > Guys, let's figure out what we are doing with this patch.
>> > --
>>
>> Oh well, patch is fine, please apply it, thanks !
>
>I'm not to sure that the patch doesn't generate a software byteswap
>followed by a byteswapping write on ppc - clearly not ideal.
>It might even generate back to back software byteswaps.
>
>If the write to the doorbell register includes a byteswap on BE (ppc)
>then there is no real value in keeping the value as BE.
>
>OTOH ppc ought to have ways of doing IO writes without the byteswap
>(and byteswapping accesses to non-io memory for that matter).
>
>What happens on a BE system with BE peripherals is another matter.
David
Thanks for your comment.
How about use __raw_writel() to replace the iowrite32()? Looks this is better,
if so, I will make up another version for this.
>
> David
>
--
Richard Yang
Help you, Help me
next prev parent reply other threads:[~2014-12-08 14:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-30 2:43 [PATCH net] net/mlx4_en: correct the endianness of doorbell_qpn on big endian platform Wei Yang
2014-11-30 2:52 ` Wei Yang
2014-11-30 19:27 ` Eric Dumazet
2014-12-01 1:29 ` Wei Yang
2014-12-06 5:31 ` David Miller
2014-12-06 5:46 ` Eric Dumazet
2014-12-08 3:12 ` Wei Yang
2014-12-08 10:00 ` David Laight
2014-12-08 14:42 ` Wei Yang [this message]
2014-12-13 3:13 ` Wei Yang
2014-12-14 4:43 ` David Miller
2014-12-15 1:32 ` Wei Yang
2014-12-15 9:59 ` Amir Vadai
2014-12-15 10:00 ` David Laight
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