[lkml]   [2011]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 9/9 (originally 8)] ARM: etm: Power down etm(s) when tracing is not enabled
Without this change a saw an 18% increase in idle power consumption
on one deivce when trace support is compiled into the kernel. Now
I see the same increase only when tracing.

Signed-off-by: Arve Hjønnevåg <>
arch/arm/kernel/etm.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
index 48de5a4..f2bc95e 100644
--- a/arch/arm/kernel/etm.c
+++ b/arch/arm/kernel/etm.c
@@ -199,7 +199,7 @@ static int trace_stop_etm(struct tracectx *t, int id)

etm_unlock(t, id);

- etm_writel(t, id, 0x440, ETMR_CTRL);
+ etm_writel(t, id, 0x441, ETMR_CTRL);
while (!(etm_readl(t, id, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
if (!timeout) {
@@ -738,7 +738,7 @@ static int __init etm_probe(struct amba_device *dev, struct amba_id *id)
(void)etm_readl(&tracer, t->etm_regs_count, ETMMR_OSSRR);

t->ncmppairs = etm_readl(t, t->etm_regs_count, ETMR_CONFCODE) & 0xf;
- etm_writel(t, t->etm_regs_count, 0x440, ETMR_CTRL);
+ etm_writel(t, t->etm_regs_count, 0x441, ETMR_CTRL);
etm_writel(t, t->etm_regs_count, new_count, ETMR_TRACEIDR);
etm_lock(t, t->etm_regs_count);

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2011-02-24 02:39    [W:0.089 / U:24.672 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site