[PATCH v2 RESEND 1/3] clocksource/vt8500: Use MIN_OSCR_DELTA from PXA
From: Thomas Gleixner <hidden>
Date: 2016-01-01 09:59:12
Also in:
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On Thu, 31 Dec 2015, Roman Volkov wrote:
From: Roman Volkov <redacted> Since vt8500 and PXA timers are identical, use MIN_OSCR_DELTA from PXA, which is bigger than existing value. It is required to determine the minimum delay which hardware can generate.
This changelog makes no sense at all.
This commit fixes vt8500 breakage in Linux 4.2 introduced by
c6eb3f7 ('hrtimer: Get rid of hrtimer softirq')quoted hunk ↗ jump to hunk
Signed-off-by: Roman Volkov <redacted> --- drivers/clocksource/vt8500_timer.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)diff --git a/drivers/clocksource/vt8500_timer.c b/drivers/clocksource/vt8500_timer.c index a92e94b..dfc3bb4 100644 --- a/drivers/clocksource/vt8500_timer.c +++ b/drivers/clocksource/vt8500_timer.c@@ -50,6 +50,8 @@ #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t) +#define MIN_OSCR_DELTA 16 + static void __iomem *regbase; static cycle_t vt8500_timer_read(struct clocksource *cs)@@ -80,7 +82,7 @@ static int vt8500_timer_set_next_event(unsigned long cycles, cpu_relax(); writel((unsigned long)alarm, regbase + TIMER_MATCH_VAL); - if ((signed)(alarm - clocksource.read(&clocksource)) <= 16) + if ((signed)(alarm - clocksource.read(&clocksource)) <= MIN_OSCR_DELTA)
So how is that value bigger? MIN_OSCR_DELTA is still 16
quoted hunk ↗ jump to hunk
return -ETIME; writel(1, regbase + TIMER_IER_VAL);@@ -151,7 +153,7 @@ static void __init vt8500_timer_init(struct device_node *np) pr_err("%s: setup_irq failed for %s\n", __func__, clockevent.name); clockevents_config_and_register(&clockevent, VT8500_TIMER_HZ, - 4, 0xf0000000); + MIN_OSCR_DELTA * 2, 0xf0000000);
Now here is the real change. You use a larger minimum tick value so that the above check in vt8500_timer_set_next_event() actually works. That's what you want to explain in the changelog. The blurb about reusing MIN_OSCR_DELTA is just useless. A proper changelog describes: 1) the problem and the resulting wreckage 2) the solution Thanks, tglx