Re: [PATCH 1/2] power: supply: bq27xxx_battery: Notify about all battery changes
From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2020-06-16 11:57:56
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From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2020-06-16 11:57:56
Also in:
lkml
On Tue, Jun 16, 2020 at 12:52:24PM +0200, Pavel Machek wrote:
On Tue 2020-05-26 21:24:39, Andrew F. Davis wrote:quoted
On 5/25/20 10:11 AM, Krzysztof Kozlowski wrote:quoted
All battery related data could be important for user-space. For example time-to-full could be shown to user on the screen or health could be monitored for any issues. Instead of comparing few selected old/new values, just check if anything changed in the cache.At least some value will change every time we poll the battery, are we okay with having power_supply_changed() called every time?I believe that's very bad idea. AFAICT that would wake up userspace every 5 seconds, eating power in unexpected way, and without easy ability of opting out. IOW a regression.
It won't be 5 seconds but poll_interval which is 360 seconds by default. It can be 5 seconds if user-space changes this time or if user-space keeps asking for get_property. In first case: user-space kind of decided about it... In second: user-space is already woken-up since it polls get properties. However I understand that this is quite intrusive change and maybe in such case user-space should just keep polling (if it wants all data to be provided every n-seconds). Best regards, Krzysztof