Date: Wed, 5 Feb 2014 13:39:56 +0000
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Joe Perches <joe@perches.com>
Cc: Holger Schurig <holgerschurig@gmail.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Sujith Manoharan <sujith@msujith.org>,
	ath9k-devel <ath9k-devel@lists.ath9k.org>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	John Linville <linville@tuxdriver.com>
Subject: Re: [ath9k-devel] [PATCH 1/3] ath9k: Fix build error on ARM
Message-ID: <20140205133956.GQ26684@n2100.arm.linux.org.uk> (sfid-20140205_144017_637573_B836FDE2)
References: <1391483274-20331-1-git-send-email-sujith@msujith.org> <1391483274-20331-2-git-send-email-sujith@msujith.org> <1391484878.2538.11.camel@joe-AO722> <21232.24855.201543.400943@gargle.gargle.HOWL> <CAOpc7mFQZ3efZda0cC28BLATqRDJ99BRNu=ezQq8wa+dyFyOvA@mail.gmail.com> <1391531796.2538.21.camel@joe-AO722> <20140205115035.GO26684@n2100.arm.linux.org.uk> <1391603566.2538.63.camel@joe-AO722> <20140205124127.GP26684@n2100.arm.linux.org.uk> <1391605494.2538.68.camel@joe-AO722>
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On Wed, Feb 05, 2014 at 05:04:54AM -0800, Joe Perches wrote:
> On Wed, 2014-02-05 at 12:41 +0000, Russell King - ARM Linux wrote:
> > On Wed, Feb 05, 2014 at 04:32:46AM -0800, Joe Perches wrote:
> > > Apparently, people just convert stupidly large udelay()s
> > > to mdelay and not be bothered.
> > 
> > And that's the correct answer.  Having udelay(10000) rather than mdelay(10)
> > is a sign that they weren't paying that much attention when writing the
> > code.
> 
> Not really.
> 
> Look at the code that brought this up in the first place.
> 
> On Tue, 2014-02-04 at 08:37 +0530, Sujith Manoharan wrote:
> > From: Sujith Manoharan <c_manoha@qca.qualcomm.com>
> > 
> > Use mdelay instead of udelay to fix this error:
> > 
> > ERROR: "__bad_udelay" [drivers/net/wireless/ath/ath9k/ath9k_hw.ko] undefined!
> []
> diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
> []
> > @@ -1316,7 +1316,7 @@ static bool ath9k_hw_set_reset(struct ath_hw *ah, int type)
> >  	if (AR_SREV_9300_20_OR_LATER(ah))
> >  		udelay(50);
> >  	else if (AR_SREV_9100(ah))
> > -		udelay(10000);
> > +		mdelay(10);
> >  	else
> >  		udelay(100);
> >  
> > 
> > >     if (AR_SREV_9300_20_OR_LATER(ah))
> > >             udelay(50);
> > >     else if (AR_SREV_9100(ah))
> > > -           udelay(10000);
> > > +           mdelay(10);
> > >     else
> > >             udelay(100);
> 
> One chip needs a larger delay than the others.
> 
> It's not so much not paying attention as not
> knowing ARM is broken for large udelay().

And now read my suggestion about how to avoid the "not knowing" problem. :)

-- 
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in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad.
Estimate before purchase was "up to 13.2Mbit".