Messages in this thread | | | Subject | Re: PM regression with LED changes in next-20161109 | From | Jacek Anaszewski <> | Date | Wed, 9 Nov 2016 21:45:28 +0100 |
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Hi Tony,
On 11/09/2016 08:23 PM, Tony Lindgren wrote: > 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?
Thanks for the report. This is probably caused by sysfs_notify_dirent(). I'm afraid that we can't keep this feature in the current shape. Hans, I'm dropping the patch. We probably will have to delegate this call to a workqueue task. Think about use cases when the LED is blinked with high frequency e.g. from ledtrig-disk.c.
Also, IMHO the notifications should be enabled only if explicitly selected in the kernel config.
-- Best regards, Jacek Anaszewski
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