Ticket #8443 (new defect)
Battery Percentage doesn't update until minutes after resume
|Reported by:||gnu||Owned by:||cjb|
|Priority:||high||Milestone:||8.2.0 (was Update.2)|
|Component:||power manager (OHM)||Version:||Development build as of this date|
|Keywords:||blocks-:8.2.0 polish:8.2.0 cjbfor8.2 relnote||Cc:||dsaxena, dilinger, smithbone, mikus@…|
|Deployments affected:||Blocked By:|
C2, Q2E15, 8.2-759.
After the XO comes out of a lid-close suspend, it lies about the state of its battery. The battery could be significantly changed from its state when it went into suspend. But the "My Battery" display does not change for minutes -- perhaps until a 1% change is seen by the CPU -- even though the battery charge itself has changed. Then it suddenly jumps to a new value.
This is not the same bug as #8010. In #8010, the battery percentage didn't update until capacity reached 14% (low battery warning). That got fixed. In this bug, it doesn't update until the battery changes by 1% AFTER resume -- even though the capacity changed WHILE SUSPENDED.
Fix: When resuming, always refresh the current battery status by polling the battery, rather than awaiting a 1%-change notification.
Remove AC power from a laptop. Put the cursor in the bottom right corner, bringing up the Frame. Put the cursor on the battery symbol until it displays the percentage full. Note the percentage. Close the lid. Now leave the laptop suspended for many hours. Open the lid. If the bug still exists, the percentage on the screen will be unchanged. If the bug still exists, you can move the cursor to remove the Frame, re-bring up the Frame, hover over the battery, and it will again tell you the same old percentage. If the bug still exists, and you leave the cursor hovering on the battery, at an unpredictable time after many minutes, the battery percentage will suddenly jump to a new number, without going through any of the intervening numbers.
You can also trigger this bug by closing the lid on a somewhat depleted battery, then plugging it into power while it's closed, letting it charge a while, then opening the lid. You'll see the old battery charge, not the new one, on the screen. This value will persist for minutes. If you want to see the real value, remove the AC power; the display will jump to the real charge percentage.
I did not test this case, but you may be able to trigger this bug by closing the lid on a somewhat depleted battery, then plugging it into power while it's closed, charging it fully, then opening the lid. You'll see the old battery charge, and this bogus value will probably persist indefinitely, since when it's already full the laptop will neither deplete the battery by 1% nor increase its charge by 1%. Removing AC power should cause it to update.