26d65140e9
Amlogic's vendor kernel defines an OPP for the GPU on Meson8b boards
with a voltage of 1.15V. It turns out that the vendor kernel relies on
the bootloader to set up the voltage. The bootloader however sets a
fixed voltage of 1.10V.
Amlogic's patched u-boot sources (uboot-2015-01-15-23a3562521) confirm
this:
$ grep -oiE "VDD(EE|AO)_VOLTAGE[ ]+[0-9]+" board/amlogic/configs/m8b_*
board/amlogic/configs/m8b_m100_v1.h:VDDAO_VOLTAGE 1100
board/amlogic/configs/m8b_m101_v1.h:VDDAO_VOLTAGE 1100
board/amlogic/configs/m8b_m102_v1.h:VDDAO_VOLTAGE 1100
board/amlogic/configs/m8b_m200_v1.h:VDDAO_VOLTAGE 1100
board/amlogic/configs/m8b_m201_v1.h:VDDEE_VOLTAGE 1100
board/amlogic/configs/m8b_m201_v1.h:VDDEE_VOLTAGE 1100
board/amlogic/configs/m8b_m202_v1.h:VDDEE_VOLTAGE 1100
Another hint at this is the VDDEE voltage on the EC-100 and Odroid-C1
boards. The VDDEE regulator supplies the Mali GPU. It's basically a copy
of the VCCK (CPU supply) which means it's limited to 0.86V to 1.14V.
Update the operating voltage of the Mali GPU on Meson8b to 1.10V so it
matches with what the vendor u-boot sets.
Fixes:
|
||
---|---|---|
Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
README
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.