Hi,
On 11/10/2016 09:29 PM, Pavel Machek wrote:
On Thu 2016-11-10 10:55:37, Tony Lindgren wrote:
* Pavel Machek <pavel@xxxxxx> [161110 09:29]:
Hi!
Looks like commit 883d32ce3385 ("leds: core: Add support for poll()ing
the sysfs brightness attr for changes.") breaks runtime PM for me.
On my omap dm3730 based test system, idle power consumption is over 70
times higher now with this patch! It goes from about 6mW for the core
system to over 440mW during idle meaning there's some busy timer now
active.
Reverting this patch fixes the issue. Any ideas?
Are you using any LED that toggles with high frequency? Like perhaps
LED that is lit when CPU is active?
Yeah one of them seems to have cpu0 as the default trigger.
Aha. Its quite obvious we don't want to notify sysfs each time that
one is toggled, right?
IMO brightness should display max brightness for the trigger, as Hans
suggested, anything else is madness for trigger such as cpu activity.
Are you suggesting that we should revert changes introduced
by below patch?
commit 29d76dfa29fe22583aefddccda0bc56aa81035dc
Author: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx>
Date: Tue Mar 18 09:47:48 2008 +0000
leds: Add support to leds with readable status
Some led hardware allows drivers to query the led state, and this patch
adds a hook to let the led class take advantage of that information
when
available.
Without this functionality, when access to the led hardware is not
exclusive (i.e. firmware or hardware might change its state behind the
kernel's back), reality goes out of sync with the led class' idea
of what
the led is doing, which is annoying at best.
Behaviour for drivers that do not or cannot read the led status is
unchanged.
Signed-off-by: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx>
Signed-off-by: Richard Purdie <rpurdie@xxxxxxxxx>
--
Best regards,
Jacek Anaszewski
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