From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Ludovic Desroches <ludovic.desroches@atmel.com>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>,
nicolas.ferre@atmel.com, linux-kernel@vger.kernel.org,
Marc Pignat <marc.pignat@hevs.ch>,
john.stultz@linaro.org, kernel@pengutronix.de,
Ronald Wahl <ronald.wahl@raritan.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] [PATCH] clocksource: tcb: fix min_delta calculation
Date: Tue, 17 Sep 2013 11:04:17 +0100 [thread overview]
Message-ID: <20130917100417.GQ12758@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20130917095600.GJ26819@ludovic.desroches@atmel.com>
On Tue, Sep 17, 2013 at 11:56:00AM +0200, Ludovic Desroches wrote:
> Any reason to not do this:
>
> --- a/drivers/clocksource/tcb_clksrc.c
> +++ b/drivers/clocksource/tcb_clksrc.c
> @@ -144,6 +144,9 @@ static void tc_mode(enum clock_event_mode m, struct
> clock_event_device *d)
>
> static int tc_next_event(unsigned long delta, struct clock_event_device
> *d)
> {
> + if (delta < d->min_delta_ticks)
> + delta = d->min_delta_ticks;
> +
> __raw_writel(delta, tcaddr + ATMEL_TC_REG(2, RC));
>
> /* go go gadget! */
>
> Then we can keep the same min_delta.
You really should not play such games in your set_next_event() code - if
the interval is not supported, you should return -ETIME so that the core
code knows about it and can adjust things to suit. If you're getting
deltas which are too small for the hardware, that'll either be because
the bounds are wrong, or there's a bug in the core code.
next prev parent reply other threads:[~2013-09-17 10:04 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-13 13:02 [PATCH] [PATCH] clocksource: tcb: fix min_delta calculation Marc Kleine-Budde
[not found] ` <20130917095600.GJ26819@ludovic.desroches@atmel.com>
2013-09-17 10:04 ` Russell King - ARM Linux [this message]
2013-09-17 11:26 ` Thomas Gleixner
[not found] ` <20130917130153.GL26819@ludovic.desroches@atmel.com>
2013-09-17 21:15 ` [PATCH] clockevents: Sanitize ticks to nsec conversion Thomas Gleixner
2013-09-17 22:25 ` Marc Kleine-Budde
2013-09-17 23:20 ` Thomas Gleixner
2013-09-18 8:56 ` Uwe Kleine-König
2013-09-18 9:38 ` Thomas Gleixner
2013-09-18 15:09 ` Uwe Kleine-König
2013-09-18 22:01 ` Thomas Gleixner
2013-09-19 10:02 ` Uwe Kleine-König
2013-09-19 10:15 ` Thomas Gleixner
2013-09-19 12:48 ` Uwe Kleine-König
2013-09-19 13:12 ` Thomas Gleixner
2013-09-19 14:30 ` Thomas Gleixner
2013-09-19 20:03 ` Uwe Kleine-König
2013-09-20 9:56 ` Thomas Gleixner
2013-09-20 20:41 ` Uwe Kleine-König
2013-09-20 21:30 ` Thomas Gleixner
2013-09-24 19:50 ` [PATCH v2] " Uwe Kleine-König
2013-09-24 21:11 ` Timekeeping on at91rm9200 [Was: [PATCH v2] clockevents: Sanitize ticks to nsec conversion] Uwe Kleine-König
2013-10-04 10:00 ` Nicolas Ferre
2013-09-24 21:16 ` [PATCH v2] clockevents: Sanitize ticks to nsec conversion Uwe Kleine-König
2013-10-08 10:08 ` Marc Kleine-Budde
2013-10-08 15:31 ` [GIT PULL] fixes for integer rounding in timer core (Was: [PATCH v2] clockevents: Sanitize ticks to nsec conversion) Uwe Kleine-König
2013-10-14 7:34 ` [GIT PULL] fixes for integer rounding in timer core Uwe Kleine-König
2013-10-16 14:19 ` Nicolas Ferre
2013-10-21 7:12 ` Uwe Kleine-König
2013-10-21 20:53 ` Daniel Lezcano
2013-10-23 10:56 ` [tip:timers/urgent] clockevents: Sanitize ticks to nsec conversion tip-bot for Thomas Gleixner
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