Re: [Intel-wired-lan] [PATCH] e1000e: changed some expensive calls of udelay to usleep_range

From	Pavel Machek <pavel@ucw.cz>
Newsgroups	linux.kernel
Subject	Re: [Intel-wired-lan] [PATCH] e1000e: changed some expensive calls of udelay to usleep_range
Date	2017-09-08 11:30 +0200
Message-ID	<unnLP-4OG-1@gated-at.bofh.it> (permalink)
References	<ujIYx-821-5@gated-at.bofh.it> <um2q6-7L6-13@gated-at.bofh.it> <undt8-6g1-11@gated-at.bofh.it>
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On Thu 2017-09-07 22:19:47, Brown, Aaron F wrote:
> > From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On
> > Behalf Of Pavel Machek
> > Sent: Monday, September 4, 2017 9:26 AM
> > To: Matthew Tan <matthew.tan_1@nxp.com>
> > Cc: michael.kardonik@nxp.com; Williams, Mitch A
> > <mitch.a.williams@intel.com>; linux-kernel@vger.kernel.org;
> > john.ronciak@intel.com; intel-wired-lan@lists.osuosl.org;
> > netdev@vger.kernel.org
> > Subject: Re: [Intel-wired-lan] [PATCH] e1000e: changed some expensive calls
> > of udelay to usleep_range
> > 
> > Hi!
> > 
> > > @@ -183,7 +183,7 @@ s32 e1000e_read_phy_reg_mdic(struct e1000_hw
> > *hw, u32 offset, u16 *data)
> > >  	 * reading duplicate data in the next MDIC transaction.
> > >  	 */
> > >  	if (hw->mac.type == e1000_pch2lan)
> > > -		udelay(100);
> > > +		usleep_range(90, 100);
> > >
> > >  	return 0;
> > >  }
> > 
> > Can you explain why shortening the delay is acceptable here?
> 
> Maybe it's not.
> 
> This patch is causing speed / duplex tests to fail on several of my test systems.  Specifically a Lenova laptop with an 82577 and a NUC with an i218 (though that does not mean it is limited to those or that it's not related to the individual link partner.)
>

Ok, this should be quite easy to verify -- just adjust all the ranges
to be >= original ones.

Thanks,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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Re: [PATCH] e1000e: changed some expensive calls of udelay to  usleep_range Pavel Machek <pavel@ucw.cz> - 2017-09-04 18:30 +0200
  RE: [Intel-wired-lan] [PATCH] e1000e: changed some expensive calls  of udelay to usleep_range "Brown, Aaron F" <aaron.f.brown@intel.com> - 2017-09-08 00:30 +0200
    Re: [Intel-wired-lan] [PATCH] e1000e: changed some expensive calls  of udelay to usleep_range Pavel Machek <pavel@ucw.cz> - 2017-09-08 11:30 +0200

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