mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-14 06:30:20 -04:00
5090ac9191
The PMIC GLINK driver is currently generating DisplayPort hotplug
notifications whenever something is connected to (or disconnected from)
a port regardless of the type of notification sent by the firmware.
These notifications are forwarded to user space by the DRM subsystem as
connector "change" uevents:
KERNEL[1556.223776] change /devices/platform/soc@0/ae00000.display-subsystem/ae01000.display-controller/drm/card0 (drm)
ACTION=change
DEVPATH=/devices/platform/soc@0/ae00000.display-subsystem/ae01000.display-controller/drm/card0
SUBSYSTEM=drm
HOTPLUG=1
CONNECTOR=36
DEVNAME=/dev/dri/card0
DEVTYPE=drm_minor
SEQNUM=4176
MAJOR=226
MINOR=0
On the Lenovo ThinkPad X13s and T14s, the PMIC GLINK firmware sends two
identical notifications with orientation information when connecting a
charger, each generating a bogus DRM hotplug event. On the X13s, two
such notification are also sent every 90 seconds while a charger remains
connected, which again are forwarded to user space:
port = 1, svid = ff00, mode = 255, hpd_state = 0
payload = 01 00 00 00 00 00 00 ff 00 00 00 00 00 00 00 00
Note that the firmware only sends on of these when connecting an
ethernet adapter.
Fix the spurious hotplug events by only forwarding hotplug notifications
for the Type-C DisplayPort service id. This also reduces the number of
uevents from four to two when an actual DisplayPort altmode device is
connected:
port = 0, svid = ff01, mode = 2, hpd_state = 0
payload = 00 01 02 00 f2 0c 01 ff 03 00 00 00 00 00 00 00
port = 0, svid = ff01, mode = 2, hpd_state = 1
payload = 00 01 02 00 f2 0c 01 ff 43 00 00 00 00 00 00 00
Fixes: 080b4e2485 ("soc: qcom: pmic_glink: Introduce altmode support")
Cc: stable@vger.kernel.org # 6.3
Cc: Bjorn Andersson <andersson@kernel.org>
Reported-by: Clayton Craft <clayton@craftyguy.net>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Acked-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Tested-by: Clayton Craft <clayton@craftyguy.net>
Link: https://lore.kernel.org/r/20250324132448.6134-1-johan+linaro@kernel.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
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 reStructuredText 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.