marți, 1 ianuarie 2013

Nexus 7 unexpected flickering issue

As most teams of Android Developers we have also got a Nexus 7 tablet. Being a non branded tablet means that we would get access to latest Android OS updates as soon as they are released. Nexus 7 packs quite a lot for a resonable price.

However it seems that there are some verry annoying basic issues that no one would expect for a Nexus device.

Screen Flickering

1. Turn brightness to about 10% on a Nexus 7 device - autobrightness in low light conditions does the trick

2. Open an app that will have a white page covering most of the screen (e.g. google chrome and the homepage)

3. Wait a few minutes

- What happened.

 The screen flickers.

- What you think the correct behavior should be.

No flickering.

Even though there is no official answer from neither Google nor Asus the issue seems to be both hardware and software related(our best guess). We suspect that the issues is not only hardware related because the occurrence has increased a lot after the update to JellyBean 4.1.2.

Since there were two recent updates to the JellyBean and the issue is still present it could not be the case the issue is only software related.

In our opinion this is a huge blow for Google, having released such a buggy tablet with very limited support or official information provided for such an annoying issue.

After researching the internet for a few hour it seems that Google still does not have an official response for this. Asus had replaced user tablets which suffered of this issue but most of the users still complain the issue is present on the replacement tablet.

From our experience with the tablet the issues is more visible in low light conditions with poor WiFi signal. A simple but unacceptable workaround is to set manual screen brightness to more than 30%. In this case the issues is not visible anymore.

If this alone does not reduce the flickering try this:
Disabling wifi optimization/keeping brightness above 30% is seen to fix it only temporarily which is disappointing.

As per report update, 4.2 made it worse which could also mean that a software patch can fix this for good in future. But on the other side, there are users who never faced this issue with a fresh buy and 4.2 update.
New nexus 7 users may be better off with 4.1 until there is a fix.

This is the most serious and popular bug/defect in Nexus 7. People sent their devices out for replacement because of this. 

Most people came to a conclusion that this is mostly happening when wlan is on and receiving/transmitting data. Some even sticked some sort of adhesive tape to their wlan antenna in the back cover to reduce to tx/rx power which apparently solved the problem. 

Some people suggests that this is caused by Tegra PRISM power management feature which dynamically changes brightness/color/saturation values of the screen.

Types of issues being reported with Nexus 7 Jelly Bean

– it is fair to say not every user has a problem, and some people explained that they have a bug free install. The Nexus 7 users reporting issues have mentioned a wide range of problems with Jelly Bean, but some of the most common include random rebooting, Wi-Fi dropping out often, killing apps randomly, lag on screen rotation, and a few users have experienced the brightness fluctuating when in lighting that’s not changing.

Again we have to stress that we’ve had a 50/50 split with users that have issues with Android 4.2, and those that have the update with no problems at all. One of the most common complaints seems to focus around the screen, and a flicker or change in brightness, so feel free to let us know if your device has this problem and if it had been there before the update?