Support input device hot-plugging and removal via udev #68
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backend/linux_input.c
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| @@ -170,6 +260,12 @@ void *twin_linux_input_create(twin_screen_t *screen) | |||
| twin_set_file(dummy, tm->fd, TWIN_READ, tm); | |||
| #endif | |||
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| /* Start event handling thread */ | |||
| if (pthread_create(&tm->udev_thread, NULL, twin_linux_udev_thread, tm)) { | |||
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Why do you create yet another thread for event handling? Can you deal with udev in the existing thread?
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We indeed require only one thread, the udev and evdev are now handled by one pollfd array.
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Excellent. You have discovered how effective I/O multiplexing can be for optimizing the code.
udev (userspace /dev) is a device manager for the Linux kernel. By monitoring "add" and "remove" events from udev, we can dynamically update the event device file descriptors table to enable device hot-plugging and removal. Close sysprog21#61
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| @@ -106,6 +106,7 @@ endif | |||
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| ifeq ($(CONFIG_BACKEND_FBDEV), y) | |||
| BACKEND = fbdev | |||
| TARGET_LIBS += -ludev | |||
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Mention libudev-dev dependency in top-level document.
| /* Open Linux udev (user space device manager) */ | ||
| int udev_fd = twin_linux_udev_init(&udev, &mon); | ||
| if (udev_fd < 0) { | ||
| exit(2); |
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The exit call here seems too harsh. Even if the input event thread fails, other parts of Mado should continue running - this would allow programmers to see the error messages and diagnose what went wrong. Consider handling the failure more gracefully rather than terminating the entire program.
Overview
udev(userspace /dev) is a device manager for the Linux kernel. By monitoringaddandremoveevents fromudev, we can dynamically update the event device file descriptors table to enable device hot-plugging and removal.Prerequisites
To test the modified code, compile
madowith theLinux framebufferbackend.Test procedure
Ctrl+Alt+Fn(e.g.,Ctrl+Alt+F3) and then execute:Ctrl+Alt+F1.