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From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 04/18] power: ab8500_fg: Replace msleep() with usleep_range() for greater accuracy
Date: Tue, 15 Jan 2013 13:23:28 +0000	[thread overview]
Message-ID: <201301151323.28879.arnd@arndb.de> (raw)
In-Reply-To: <20130115084821.GT12385@gmail.com>

On Tuesday 15 January 2013, Lee Jones wrote:
> > > @@ -956,7 +956,7 @@ static int ab8500_fg_load_comp_volt_to_capacity(struct ab8500_fg *di)
> > >     do {
> > >             vbat += ab8500_fg_bat_voltage(di);
> > >             i++;
> > > -           msleep(5);
> > > +           usleep_range(5000, 5001);
> > 
> > If you're going to give a range that small
> > you might as well use usleep instead.
> > 
> > Otherwise, add some tolerance to allow any
> > other coalesced wakeup to occur.
> 
> I can't increase the tolerance, as I don't know how that would
> effect the running of the system, and the person who would know
> is off on parental leave.

The function only averages the voltage between a couple of readings.
It won't change much if those register reads are slightly more
uniformly timed. Note that the thread can still be preempted for
a much longer time if anything else is running, and the entire
interrupt handling in this driver looks so fragile that I would
not rely on the interrupt actually happening at the right time
anyway. I think it should first be debugged properly to remove
the need for the enable_irq/disable_irq calls.

	Arnd

  parent reply	other threads:[~2013-01-15 13:23 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-11 13:12 [PATCH 00/18] AB8500 battery management series upgrade Lee Jones
2013-01-11 13:12 ` [PATCH 01/18] power: ab8500_charger: Rename the power_loss function Lee Jones
2013-01-11 13:12 ` [PATCH 02/18] power: ab8500_bm: Skip first CCEOC irq for instant current Lee Jones
2013-01-11 13:12 ` [PATCH 03/18] power: ab8500_charger: Detect charger removal Lee Jones
2013-01-16  1:36   ` Anton Vorontsov
2013-01-16  8:48     ` Lee Jones
2013-01-11 13:12 ` [PATCH 04/18] power: ab8500_fg: Replace msleep() with usleep_range() for greater accuracy Lee Jones
2013-01-14 17:17   ` Joe Perches
2013-01-15  8:48     ` Lee Jones
2013-01-15  8:59       ` Linus Walleij
2013-01-15 13:23       ` Arnd Bergmann [this message]
2013-01-15 13:52         ` Lee Jones
2013-01-15 14:09   ` Lee Jones
2013-01-11 13:12 ` [PATCH 05/18] power: ab8500_charger: Handle gpadc errors Lee Jones
2013-01-11 13:12 ` [PATCH 06/18] power: ab8500_bm: Recharge condition not optimal for battery Lee Jones
2013-01-16  1:44   ` Anton Vorontsov
2013-01-16  8:47     ` Lee Jones
2013-01-11 13:12 ` [PATCH 07/18] power: ab8500_fg: balance IRQ enable Lee Jones
2013-01-11 13:12 ` [PATCH 08/18] power: ab8500_btemp: Allign battery temperature resolution with the framework Lee Jones
2013-01-11 13:12 ` [PATCH 09/18] power: ab8500_btemp: Ignore false btemp low interrupt Lee Jones
2013-01-11 13:12 ` [PATCH 10/18] power: ab8500_bm: Adds support for Car/Travel Adapters Lee Jones
2013-01-11 13:12 ` [PATCH 11/18] power: ab8500_fg: Round capacity output Lee Jones
2013-01-11 13:13 ` [PATCH 12/18] power: ab8500_btemp: remove superfluous BTEMP thermal comp Lee Jones
2013-01-11 13:13 ` [PATCH 13/18] power: ab8500_fg: Added support for BATT_OVV Lee Jones
2013-01-11 13:13 ` [PATCH 14/18] power: pm2301: Add pm2301 charger Lee Jones
2013-01-16  1:37   ` Anton Vorontsov
2013-01-11 13:13 ` [PATCH 15/18] power: ab8500_charger: remove unused defines Lee Jones
2013-01-11 13:13 ` [PATCH 16/18] power: ab8500_charger: Adds support for legacy USB chargers Lee Jones
2013-01-11 13:13 ` [PATCH 17/18] Power: ab8500_fg: Overflow in current calculation Lee Jones
2013-01-11 13:13 ` [PATCH 18/18] power: ab8500_fg: Remove pointless round_jiffies() call Lee Jones
2013-01-16  1:48 ` [PATCH 00/18] AB8500 battery management series upgrade Anton Vorontsov
2013-01-16  8:50   ` Lee Jones

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