linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: Anton Vorontsov <avorontsov@ru.mvista.com>
To: Kumar Gopalpet-B05799 <B05799@freescale.com>
Cc: linuxppc-dev list <linuxppc-dev@ozlabs.org>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Martyn Welch <martyn.welch@ge.com>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	davem@davemloft.net
Subject: Re: Gianfar driver failing on MPC8641D based board
Date: Tue, 2 Mar 2010 17:02:33 +0300	[thread overview]
Message-ID: <20100302140233.GA14488@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <9F4C7D19E8361D4C94921B95BE08B81BC93EC3@zin33exm22.fsl.freescale.net>

Hi!

On Sat, Feb 27, 2010 at 11:05:32AM +0530, Kumar Gopalpet-B05799 wrote:
[...]
> Understood, and thanks for the explanation. Am I correct in saying that
> this is
> due to the out-of-order execution capability on powerpc ?

Nope, that was just a logic issue in the driver. 

Though, with the patch, the eieio() is needed so that compiler (or CPU)
won't reorder lstatus and skbuff writes.

> I have one more question, why don't we use use atomic_t for num_txbdfree
> and
> completely  do away with spin_locks in gfar_clean_tx_ring() and
> gfar_start_xmit().
> In an non-SMP, scenario I would feel there is absolutely no requirement
> of spin_locks
> and in case of SMP atomic operation would be much more safer on powerpc
> rather than spin_locks.
> 
> What is your suggestion ?

I think that's a good idea.

However, in start_xmit() we'll have to keep the spinlock anyway
since it also protects from gfar_error(), which can modify
regs->tstat.

Thanks!

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2

  reply	other threads:[~2010-03-02 14:02 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-05 14:00 Gianfar driver failing on MPC8641D based board Martyn Welch
2010-02-25 10:31 ` Martyn Welch
2010-02-25 16:46   ` Martyn Welch
2010-02-25 16:51     ` Anton Vorontsov
2010-02-25 17:49       ` Anton Vorontsov
2010-02-26  0:53         ` Paul Gortmaker
2010-02-26  3:14           ` Anton Vorontsov
2010-02-26  4:58             ` Kumar Gopalpet-B05799
2010-02-26 12:06             ` Martyn Welch
2010-02-26 14:35               ` Anton Vorontsov
2010-02-26 14:52                 ` Paul Gortmaker
2010-02-26 15:18                   ` Martyn Welch
2010-02-26 15:34                     ` Martyn Welch
2010-02-26 16:10                       ` Anton Vorontsov
2010-02-26 16:27                         ` Paul Gortmaker
2010-02-26 21:38                           ` Anton Vorontsov
2010-02-26 22:12                             ` Paul Gortmaker
2010-02-27  5:35                             ` Kumar Gopalpet-B05799
2010-03-02 14:02                               ` Anton Vorontsov [this message]
2010-03-01 13:07                             ` Martyn Welch
2010-02-26 11:51       ` Martyn Welch
2010-02-25 18:27     ` Kumar Gala

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20100302140233.GA14488@oksana.dev.rtsoft.ru \
    --to=avorontsov@ru.mvista.com \
    --cc=B05799@freescale.com \
    --cc=davem@davemloft.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@ozlabs.org \
    --cc=martyn.welch@ge.com \
    --cc=netdev@vger.kernel.org \
    --cc=paul.gortmaker@windriver.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).