Since commit 01426478df3a8791ff5c8b6b82d409e699cfaf38
(avr32: Use generic idle loop) the kernel throws the
following warning on avr32:
WARNING: at 900322e4 [verbose debug info unavailable]
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 3.12.0-rc2 #117
task: 901c3ecc ti: 901c0000 task.ti: 901c0000
PC is at cpu_idle_poll_ctrl+0x1c/0x38
LR is at comparator_mode+0x3e/0x40
pc : [<900322e4>] lr : [<90014882>] Not tainted
sp : 901c1f74 r12: 00000000 r11: 901c74a0
r10: 901d2510 r9 : 00000001 r8 : 901db4de
r7 : 901c74a0 r6 : 00000001 r5 : 00410020 r4 : 901db574
r3 : 00410024 r2 : 90206fe0 r1 : 00000000 r0 : 007f0000
Flags: qvnzc
Mode bits: hjmde....G
CPU Mode: Supervisor
Call trace:
[<90039ede>] clockevents_set_mode+0x16/0x2e
[<90039f00>] clockevents_shutdown+0xa/0x1e
[<9003a078>] clockevents_exchange_device+0x58/0x70
[<9003a78c>] tick_check_new_device+0x38/0x54
[<9003a1a2>] clockevents_register_device+0x32/0x90
[<900035c4>] time_init+0xa8/0x108
[<90000520>] start_kernel+0x128/0x23c
When the 'avr32_comparator' clockevent device is registered,
the clockevent core sets the mode of that clockevent device
to CLOCK_EVT_MODE_SHUTDOWN. Due to this, the 'comparator_mode'
function calls the 'cpu_idle_poll_ctrl' to disables idle poll.
This results in the aforementioned warning because the polling
is not enabled yet.
Change the code to only disable idle poll if it is enabled by
the same function to avoid the warning.
Cc: [email protected]
Signed-off-by: Gabor Juhos <[email protected]>
---
Note: the patch is against v3.12-rc2.
---
arch/avr32/kernel/time.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/avr32/kernel/time.c b/arch/avr32/kernel/time.c
index 869a1c6..12f828a 100644
--- a/arch/avr32/kernel/time.c
+++ b/arch/avr32/kernel/time.c
@@ -98,7 +98,14 @@ static void comparator_mode(enum clock_event_mode mode,
case CLOCK_EVT_MODE_SHUTDOWN:
sysreg_write(COMPARE, 0);
pr_debug("%s: stop\n", evdev->name);
- cpu_idle_poll_ctrl(false);
+ if (evdev->mode == CLOCK_EVT_MODE_ONESHOT ||
+ evdev->mode == CLOCK_EVT_MODE_RESUME) {
+ /*
+ * Only disable idle poll if we have forced that
+ * in a previous call.
+ */
+ cpu_idle_poll_ctrl(false);
+ }
break;
default:
BUG();
--
1.7.10
Around Wed 25 Sep 2013 11:31:19 +0200 or thereabout, Gabor Juhos wrote:
> Since commit 01426478df3a8791ff5c8b6b82d409e699cfaf38
> (avr32: Use generic idle loop) the kernel throws the
> following warning on avr32:
>
> WARNING: at 900322e4 [verbose debug info unavailable]
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper Not tainted 3.12.0-rc2 #117
> task: 901c3ecc ti: 901c0000 task.ti: 901c0000
> PC is at cpu_idle_poll_ctrl+0x1c/0x38
> LR is at comparator_mode+0x3e/0x40
> pc : [<900322e4>] lr : [<90014882>] Not tainted
> sp : 901c1f74 r12: 00000000 r11: 901c74a0
> r10: 901d2510 r9 : 00000001 r8 : 901db4de
> r7 : 901c74a0 r6 : 00000001 r5 : 00410020 r4 : 901db574
> r3 : 00410024 r2 : 90206fe0 r1 : 00000000 r0 : 007f0000
> Flags: qvnzc
> Mode bits: hjmde....G
> CPU Mode: Supervisor
> Call trace:
> [<90039ede>] clockevents_set_mode+0x16/0x2e
> [<90039f00>] clockevents_shutdown+0xa/0x1e
> [<9003a078>] clockevents_exchange_device+0x58/0x70
> [<9003a78c>] tick_check_new_device+0x38/0x54
> [<9003a1a2>] clockevents_register_device+0x32/0x90
> [<900035c4>] time_init+0xa8/0x108
> [<90000520>] start_kernel+0x128/0x23c
>
> When the 'avr32_comparator' clockevent device is registered,
> the clockevent core sets the mode of that clockevent device
> to CLOCK_EVT_MODE_SHUTDOWN. Due to this, the 'comparator_mode'
> function calls the 'cpu_idle_poll_ctrl' to disables idle poll.
> This results in the aforementioned warning because the polling
> is not enabled yet.
>
> Change the code to only disable idle poll if it is enabled by
> the same function to avoid the warning.
Thank you for fixing.
> Cc: [email protected]
> Signed-off-by: Gabor Juhos <[email protected]>
Acked-by: Hans-Christian Egtvedt <[email protected]>
> ---
> Note: the patch is against v3.12-rc2.
> ---
I'll add this to my for-linus branch, which I'll send a pull request for
soon.
> arch/avr32/kernel/time.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/avr32/kernel/time.c b/arch/avr32/kernel/time.c
> index 869a1c6..12f828a 100644
> --- a/arch/avr32/kernel/time.c
> +++ b/arch/avr32/kernel/time.c
> @@ -98,7 +98,14 @@ static void comparator_mode(enum clock_event_mode mode,
> case CLOCK_EVT_MODE_SHUTDOWN:
> sysreg_write(COMPARE, 0);
> pr_debug("%s: stop\n", evdev->name);
> - cpu_idle_poll_ctrl(false);
> + if (evdev->mode == CLOCK_EVT_MODE_ONESHOT ||
> + evdev->mode == CLOCK_EVT_MODE_RESUME) {
> + /*
> + * Only disable idle poll if we have forced that
> + * in a previous call.
> + */
> + cpu_idle_poll_ctrl(false);
> + }
> break;
> default:
> BUG();
--
mvh
Hans-Christian Egtvedt