As smartphone manufacturers scramble to incorporate notch designs into their displays, another display technology continues to plod along slowly toward wider adoption, the in-display fingerprint sensor. Such a sensor makes a separate button unnecessary as a layer in the display itself is used to detect and read a user's fingerprint. Manufacturers have been working for quite a while now to make this a reality. In recent months some smaller companies like Vivo managed to actually get a product to market with an in-display sensor and Huawei managed to use one in their limited edition Huawei Porsche Design Mate RS. Others, like Samsung, may release devices later this year with in-display fingerprint sensors. According to sources, Xiaomi appears to be one of the companies that will be in a position to do so.
The device that appears to be pegged for introduction of the in-display fingerprint sensor is the Xiaomi Mi 7 Plus. This conclusion was reached after developers had a chance to dive into some of the firmware code for the devices that Xiaomi has in developmet, including ursa and dipper, which are believed to be the Mi 7 Plus and Mi 7 respectively. The code includes traces that point to an in-display sensor such as the text string “fod” that is thought to stand for “fingerprint on display.” In some cases that reference was combined with “goodix” where Goodix is one of the big producers of in-display fingerprint sensors alongside Synaptics.
There are other bits of code that reference “drawables” to be shown on the device screen, like “finger_circle” indicating adoption of the in-display technology is in the works.
According to the sources examining all of this code, Xiaomi has two branches for code development for the Mi 7 or dipper. One of them appears to be an old version and the other is currently active. Interestingly, the code for the in-display sensor is present in the old branch, but not in the new branch. Although a bit surprising, that is consistent with the history of the device which was in development and then dropped off the radar. Rumors suggested Xiaomi was having trouble with the fingerprint sensor technology, which caused them to pull back on their original Mi 7 release plans and schedules.
For now, the code does appear in the active development branch for the Mi 7 Plus or ursa device.
source: XDA Developers
