Re: [PATCH v2 4/9] clocksource/cadence_ttc: Use enable/disable_irq
From: Daniel Lezcano
Date: Thu Nov 28 2013 - 06:55:46 EST
On 11/27/2013 02:04 AM, Soren Brinkmann wrote:
To ensure that the timer interrupt is properly enabled/disabled across
the whole CPU cluster use enable/disable_irq() instead of
local_irq_disable().
Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx>
---
drivers/clocksource/cadence_ttc_timer.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/clocksource/cadence_ttc_timer.c b/drivers/clocksource/cadence_ttc_timer.c
index a92350b55d32..246d018d1e63 100644
--- a/drivers/clocksource/cadence_ttc_timer.c
+++ b/drivers/clocksource/cadence_ttc_timer.c
@@ -322,18 +322,16 @@ static int ttc_rate_change_clockevent_cb(struct notifier_block *nb,
switch (event) {
case POST_RATE_CHANGE:
{
- unsigned long flags;
-
/*
* clockevents_update_freq should be called with IRQ disabled on
* the CPU the timer provides events for. The timer we use is
* common to both CPUs, not sure if we need to run on both
* cores.
*/
- local_irq_save(flags);
+ disable_irq(ttcce->ce.irq);
clockevents_update_freq(&ttcce->ce,
ndata->new_rate / PRESCALE);
- local_irq_restore(flags);
+ enable_irq(ttcce->ce.irq);
/* update cached frequency */
ttc->freq = ndata->new_rate;
I am worried about the 'disable_irq' function calling 'synchronize_irq'.
Isn't possible to deadlock with the ondemand cpufreq governor ? I added
Viresh in Cc, he knows better than me the code path.
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