Lenovo Tab 4 8 (lenovo-tb8504f): Difference between revisions
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=== CPU Tuning === | |||
According to <code>cpufreq-info</code> (cpufrequtils package), the chipset does indeed have a tiny frequency range, 960MHz - 1.4GHz. Benchmarks (<code>ubench</code>) show trivial differences in performance between the available frequency governors (default is performance), and all result in thermal throttling (frequency limiting). | |||
=== Sensors === | === Sensors === |
Revision as of 21:30, 22 June 2022
![]() A Lenovo Tab 4 8 running postmarketOS | |
Manufacturer | Lenovo |
---|---|
Name | Tab 4 8 |
Codename | lenovo-tb8504f |
Released | 2017 |
Hardware | |
Chipset | Qualcomm APQ8017 |
CPU | 1.4 GHz Cortex-A53 |
GPU | Adreno 306 |
Display | 800x1280 IPS LCD |
Storage | 16GB |
Memory | 2GB |
Architecture | aarch64 |
Software | |
Original software | Android 7.0 |
postmarketOS | |
Category | testing |
Pre-built images | no |
Flashing |
Works |
---|---|
USB Networking |
Works |
Internal storage |
No data |
SD card |
No data |
Battery |
No data |
Screen |
Works |
Touchscreen |
Partial |
Multimedia | |
3D Acceleration |
Broken |
Audio |
No data |
Camera |
No data |
Camera Flash |
No data |
Connectivity | |
WiFi |
Broken |
Bluetooth |
Partial |
GPS |
No data |
NFC |
No data |
Miscellaneous | |
FDE |
No data |
USB OTG |
No data |
HDMI/DP |
No data |
Sensors | |
Accelerometer |
No data |
Magnetometer |
No data |
Ambient Light |
No data |
Proximity |
No data |
Hall Effect |
No data |
Haptics |
No data |
Barometer |
No data |
This page is about WiFi-only tablet lenovo-tb8504f. For LTE tablet, see lenovo-tb8504x. |
Contributors
- Angus-g
Users owning this device
Unlocking
In developer options the allow oem unlock toggle may be unexpectedly disabled. In this case, try a software update to confirm latest (final) version, similar to tb-8504f_s001019_190909_row. The fastboot key combo is volume down + power. No device-specific information (e.g., bootloader version) is presented on the fastboot splash screen. fastboot getvar all
shows some basic details. The standard unlock command fastboot oem unlock
gives a warning and shows the correct command.
Installation
Install TWRP (3.2.3 and 3.3.1 are available). Format the System partition to prepare for the postmarketOS image. Either install from a recovery zip directly in TWRP, or use pmbootstrap flasher
as usual.
Note: install from a recovery zip using sdcard or via sideload fail with the initramfs-extra not found
splash screen.
Status
Using the LineageOS kernel (which is derived from Lenovo's open-sourced kernel), we can boot to a graphical display with USB networking. If CONFIG_USB_G_ANDROID
is not set, it seems that there are a lot of errors regarding charging when connected via USB, and the boot doesn't get through to init. The touchscreen is detected, but the driver gets disabled in libinput due to a kernel bug.
Hardware details
Chipset
The chipset appears to be APQ8017, with an Adreno 300-series GPU. It seems to be very similar (at the devicetree level) to MSM8917. Neither of these currently have a mainline kernel effort. Wikipedia suggests the Snapdragon 425 MSM8917 is software-compatible with MSM8937.
The values are estimated strictly from software, not hardware, results (fastboot, adb, or twrp-3.3.1-1-TB8504 [unified 8504f/x)], using the commands given below.
chipset details (software-derived)
feature | value | source |
---|---|---|
variant | QRD eMMC | fastboot |
product | QC_REFERENCE_PHONE | fastboot |
baseband | fastboot | |
bootloader | fastboot | |
kernel | 3.18.71-perf-gec07f0ae-dirty Aug 2019 | adb |
Hardware | Qualcomm Technologies, Inc APQ8017 | adb |
CPU max freq (KHz?) | 1401000 | twrp |
CPU min freq (KHz?) | 960000 | twrp |
GPU model | Adreno306v33 | twrp |
GPU max freq (Hz) | 598000000 | twrp |
GPU min freq (Hz) | 270000000 | twrp |
GPU target freq (Hz) | 400000000 | twrp |
compatible | qcom,msm8917-qrd-sku5 | twrp |
model | Qualcomm Technologies, Inc. MSM8917-PMI8937 QRD SKU5 | twrp |
Bluetooth | ? | (8017 is 4.2, 8917 is 4.1?) |
sample commands (software-derived)
fastboot getvar all
cat /proc/version
cat /proc/cpuinfo
cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq
cat /sys/class/kgsl/kgsl-3d0/gpu_model
cat /sys/class/kgsl/kgsl-3d0/max_clock_mhz
cat /sys/class/kgsl/kgsl-3d0/max_gpuclk
cat /sys/class/kgsl/kgsl-3d0/min_clock_mhz
cat /sys/class/kgsl/kgsl-3d0/devfreq/target_freq
cat /sys/firmware/devicetree/base/compatible
cat /sys/firmware/devicetree/base/model
CPU Tuning
According to cpufreq-info
(cpufrequtils package), the chipset does indeed have a tiny frequency range, 960MHz - 1.4GHz. Benchmarks (ubench
) show trivial differences in performance between the available frequency governors (default is performance), and all result in thermal throttling (frequency limiting).
Sensors
For reference, output of sensorssandbox (v1.8, f-droid):
sensorssandbox results
sensor | vendor |
---|---|
BMA255 Accelerometer / Temperature / Double Tap | Bosch |
Step Detector | QTI |
Step Counter | QTI |
Significant Motion Detector | QTI |
Tilt Detector | QTI |
Basic Gestures | ? |
Facing | ? |
Pedometer | QTI |
Motion Accel | QTI |
Coarse Motion Classifier | ? |
See also
- pmaports!2048 Initial merge request
- Device package
- Kernel package