The recently launched OnePlus 5 has been in the news this week for a ‘jelly scrolling’ issue that some of its users have reported. Early adopters of the device noticed a jelly-like warping effect when scrolling through webpages and apps like Twitter. Many speculations were being made about the cause of the jelly scrolling effect, with one prominent one being it could be a VSync issue, and the other being that the display has been installed upside down in the device.
If you are wondering what the jelly scrolling effect really is, well, it's quite difficult the explain the issue in text and a video shot by The Verge’s Dan Seifert shows the ‘jelly’ effect while scrolling through the Twitter app:
OnePlus issued a statement stating that the effect is natural and there is no variance in screens between devices. Which also means that it is unlikely to get a software update to fix the issue.
Popular modding community website XDA investigated the issue and soon ruled out VSync toggling as a cause for this effect. To verify if the display is inverted, an XDA Recognized Developer ‘SultanXDA’ scanned through the kernel source code. The kernel, in simple terms, is an important link between the software and the hardware of the device.
In the kernel code, the developer found a display controller code which rotates the output by a 180 degrees. The developer confirmed that only the OnePlus 5 kernel has this line of code while other devices like the OnePlus 3, OnePlus 3T, Google Nexus 5X, and Google Nexus 6P lacked in their kernel.
Another XDA developer ‘eng.stk’ compiled the OnePlus 5’s panel code and flashed the OnePlus 3T with the code which resulted in the OnePlus 3T’s display being inverted. Because of which the controller flips the output. In a physical hardware teardown it can be seen from the display connector that the display might actually be placed upside-down.
Finally, a Reddit user has also posted in the OnePlus sub-reddit that the OnePlus 5 screen refreshes from bottom to top with the traditional behaviour being top to bottom. The user has shot a 960fps video showing how the OnePlus 5 refreshes the screen in comparison to the Google Pixel XL and the Samsung Galaxy S8+.
The unconventional refresh method could be the reason for the ‘jelly scrolling’ effect on the OnePlus 5.