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authorEduard Zingerman <eddyz87@gmail.com>2026-09-04 17:05:56 -0700
committerAlexei Starovoitov <ast@kernel.org>2026-09-04 18:17:30 -0700
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downloadlinux-stable-506ada89629ec7059b96ecfb0dc7d33ece0103ca.tar.gz
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bpf: mark a NULL kfunc argument precisegrafted
check_kfunc_arg() allows bpf_register_is_null() for nullable arguments w/o marking the underlying scalar register precise. Hence a checkpoint created on such a path would prune against arbitrary scalar value. Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)") Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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+Video Output Switcher Control
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+2006 luming.yu@intel.com
+
+The output sysfs class driver provides an abstract video output layer that
+can be used to hook platform specific methods to enable/disable video output
+device through common sysfs interface. For example, on my IBM ThinkPad T42
+laptop, The ACPI video driver registered its output devices and read/write
+method for 'state' with output sysfs class. The user interface under sysfs is::
+
+ linux:/sys/class/video_output # tree .
+ .
+ |-- CRT0
+ | |-- device -> ../../../devices/pci0000:00/0000:00:01.0
+ | |-- state
+ | |-- subsystem -> ../../../class/video_output
+ | `-- uevent
+ |-- DVI0
+ | |-- device -> ../../../devices/pci0000:00/0000:00:01.0
+ | |-- state
+ | |-- subsystem -> ../../../class/video_output
+ | `-- uevent
+ |-- LCD0
+ | |-- device -> ../../../devices/pci0000:00/0000:00:01.0
+ | |-- state
+ | |-- subsystem -> ../../../class/video_output
+ | `-- uevent
+ `-- TV0
+ |-- device -> ../../../devices/pci0000:00/0000:00:01.0
+ |-- state
+ |-- subsystem -> ../../../class/video_output
+ `-- uevent
+