mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-30 15:44:13 +08:00
3de93e6ed2
On ACPI boards, when we cannot get the GPIOs to do a reset ourselves
if necessary, call acpi_device_fix_up_power() to force the ACPI _PS0
method to run.
On some devices without proper GPIO descriptions this will reset
the touchscreen for us and this may be necessary for us to be able
to communicate to the touchscreen at all.
Specifically on an Aya Neo Next this change will cause the _PS0()
ACPI function to call INIT() which does:
Method (INIT, 0, Serialized)
{
TP_I = 0x00A50000
TP_R = 0x00A50000
Sleep (0x0A)
TP_I = 0x00E50000
Sleep (One)
TP_R = 0x00E50000
Sleep (0x06)
TP_I = 0x00A50000
Sleep (0x3C)
TP_I = 0x00041800
}
On older kernels the ACPI core assumed a power-on was necessary by itself
and would run _PS0 before our probe function runs, which can be seen from
the GPIO pin ctrl registers in /sys/kernel/debug/gpio which match
the above hex values with older kernels.
With newer kernels before this change the GPIO pin ctrl registers do not
match, indicating INIT() has not run and probing the touchscreen fails.
This change makes Linux run _PS0() again fixing the touchscreen not working
on the Aya Neo Next.
Reported-and-tested-by: Maya Matuszczyk <maccraft123mc@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220618210233.208027-1-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.