Latest version of Android 7.0 nougat Now it has been officially released. OEM manufacturers are announcing their own mobile phone upgrade plans, Sony and HTC All have been announced, and Google is also Nexus 6 、 Nexus 5X as well as Nexus 6P Released Android 7.0.
high pass
Unfortunately, some mobile phones (which also sell well) may not enjoy the feast of system upgrade. You see, Sony's upgrade plan does not include Xperia Z3, nor does HTC announce its One M8 And Google's Nexus 5 I don't know when I will be able to upgrade to Android 7.0. The above three devices have two things in common. First, they were released in 2013 or 2014 and are a bit old. But do you think Apple's iPhone 4S can be upgraded as usual? Although the card is ×; Second, they all use Qualcomm Snapdragon 800 or 801 processors.
According to foreign media on Twitter, "Qualcomm will not release graphics drivers for its 800 or 801, so HTC One M8 And other mobile phones that use this processor will not get the official Android 7.0 upgrade. "
We also consulted Qualcomm officials about this issue and got the following reply.
"We, Qualcomm Technologies Co., Ltd., have been working closely with our OEM customers to support and launch the latest Android system for all kinds of Android phones using Qualcomm processors. Whether to support the latest system depends more on the life cycle of the phone product itself. Therefore, we recommend that consumers should contact the product manufacturer to ask about system updates."
OK， According to Qualcomm, this is a product life cycle problem, that is, Sony, HTC and other manufacturers think that the phones equipped with 800/801 processors are too old, and the life cycle has come to an end, so they will not update them. But what if the OEM wants to update Android 7.0 for those phones? Can it be done?
Sony
Sony has been developing Android 7.0 for Xperia Z3, and there is also a developer preview version of Xperia Z3, which has been updated to developer preview version 4. In this case, there must be no technical problems with Android 7.0 running on Qualcomm Snapdragon 800/801, but preview version 5 has not been released yet. According to Sony, There are two problems here - technical and legal.
(Sony Xperia Z3, Android N Developer Preview)
A person in charge of Sony's mobile phone department said on the media platform: "We don't want to blame anyone, nor will we shirk responsibility. Unless we can pass Google CTS certification, we may not be able to upgrade the Android 7.0 system for Z3."
Google
It seems that Sony is blaming Google, so what is Google CTS? In order to get Google's approval (and use Google's various services such as Play Store), OEM manufacturers must comply with Android's Compatibility Definition Document * CDD, This means that basically some basic requirements and definitions have been made for the software and hardware of manufacturers, and then the equipment made by manufacturers must pass the Compatibility Test Suite, or CTS.
First of all, let's briefly explain that some people say that Qualcomm is unwilling to release the graphics driver of its own processor because it can not be updated. Qualcomm says that it is the OEM who decides whether to update or not, and Sony says that it is Google's fault~
Here is another problem. The CDD and CTS in Android 7.0 are caused by something Nexus 5 、 Can HTC One M8 and Xperia Z3 fail the audit? In terms of processors, we can analyze them in three points: the supported instruction set, GPU and performance.
We took a closer look at the devices that will receive Android 7.0 updates, and then came to the following information
The GPUs they use include Adreno 360, Adreno 430 and Mali-T860
The processor performance of these devices varies widely, from Helio P10, Snapdragon 410 to Snapdragon 820
Most devices use 64 bit processors
From the perspective of GPU of most devices, it should not be a GPU problem. All devices equipped with Adreno 306 can be updated with Android 7.0. The Mail GPU team of ARM told me that Android 7.0 supports the parallel use of Open GL ES and Vulkan, The Mali-T760 also supports Vulkan. Not only high-end GPUs such as the Mali-T880 or Mali-G71 support Vulkan, so I feel that "Qualcomm will not release graphics drivers" is somewhat untrustworthy.
Secondly, it should not be because of performance that Android 7.0 cannot be updated. You can see that even low-end devices such as Snapdragon 410 can still eat nougat, or devices such as MediaTek P1 are also OK. There is no sign that the performance of Snapdragon 801 processor can not meet the standard of system upgrade, and in my test, Snapdragon 801 is faster than Helio X10.
However, it is worth mentioning that most of the devices that can be upgraded have 64 bit processors. In other words, they are all based on ARMv8 architecture processors. What's the problem with Snapdragon 800/801? But even Snapdragon 805 is OK (32-bit processor on Nexus 6). If it is not related to GPU, performance or 32-bit or 64 bit, what is the problem that prevents them from updating the system.
ARMv8 and advanced encryption standard
My conclusion is that Google has forcibly turned on Full Disk Encryption in Android 6.0, which will lead to a sharp decline in the reading and writing performance of mobile phones. Therefore, CDD has also set a threshold for this function. The encryption performance of devices that support full disk encryption and advanced encryption standards needs to be higher than 50 MiB/s.
Android 7.0 adopts a file based encryption method, which means that it encrypts a single file rather than the entire file system. This encryption method enables the Android system to implement a more sophisticated encryption policy, and at the same time, it also enables direct boot Function. At present, the CDD of Android 7.0 has not been announced, but it will definitely make relevant regulations on AES encryption performance, and then CTS will test it.
Another function of the ARMv8 architecture processor is the hardware encryption instruction, which means that SoCs based on this architecture, such as Helio P10, Snapdragon 410 and 820 processors, can use this function and then use AES to encrypt data, which is much faster than using the software method to encrypt.
So Sony's "technical problems and legal problems" should mean that Snapdragon 800/801 cannot achieve the performance speed required for AES encryption of ARMv8 chip, because this processor does not support hardware encryption, while Qualcomm has added the hardware required for this encryption function to Snapdragon 805, which supports full disk encryption technology and encryption function for Android applications. That may be why Nexus 6 The reason why it can be upgraded to Android 7.0, but it seems that other phones with 32-bit processors cannot be upgraded.
My conclusion is that the Snapdragon 800/801 does not have any technical problems that prevent it from upgrading to Android 7.0, but Google has certain requirements for encryption speed. The Snapdragon 800/801 cannot cross the threshold of CTS and does not meet the CDD standard.
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