新编文档-Anewdevicedriverforavideoframegrabber一个视频帧捕获一个新的设备驱动程序-精品文档

1、A new device driver for a video frame grabberTerm Project 一 Kernel Device -Summer 2019Binh Tran 一 Lucie Ngnepieba1. Overview2. Our goals3. Our achievement4. 4. Difficulties and our solutions5. Discovered facts and our learns6. Future works7. Conclusion-515s?I c c01d ar cdar c To compile correctly on

2、 the Linux distribution 2.6.16 To improve the previous Video frame grabber device driver to support Video4Linux. To integrate the previous driver and make it work on both grayscale and color support.To work on the low-level operation of the frame grabber to support the new interrupt-driven I/O featu

3、re (if time permits).Previous studenfs worksTaken from the previous students journal (The device driver ran on Linux distribution 2.6.10 and 2.6.11.2. The greyscale works correctly, but thecolor was fuzzy.3. The cleanup function was inconsistent4. Kernel panic when unload the moduleOur achievements

4、Our device driver一 is stable with the 2.6.16.14 kernel一 works properly, consistently without errors( ie load module, unload module , auto-detect different devices, no kernel panic) (goal #1) Our driver supports Video4linux (goal #2) We improve the preview driver to support both grey scale and color

5、cards (goal #3)Problems found in the original device driver and our so I u t i1. When compiled and executed the hrt module was loaded, but:一 No device was detected,一 The major number did not show upSol: we put a series of debugging messages to test, and we add code in the hrt_init_module9 hrt_cleanu

6、p_module9 hrtjoad, hrt_unload.2. The two cards were detected as grayscale cards,and give us a warning message about sysfs needed.(Cont)Sol: Switched the two cards, reboot, and load module again It works We diagnose the cards slots are sensitive Moreove巧 sysfs is not a main issue.3. The pci color car

7、d was not unregistered when we unload the module(this prob panic the kernel when unloading). First found by Danny一 Sols we add lines of code to unregister the color card in the hrt_cleanup and hrt_pci_cleanup functions4. Pixels mapping among user space, kernel buffer and I/O devices do not work corr

8、ectly, the color display was fuzzy一 Sol： pixel mapping between kernel and user buf was not correct We changed the way the mapping was done in the grab.field function.一 And set the resolution in the test file to 640 x 480.(Cont)5. Missing libraries needed for Video4linux Sol： we installed SDL librari

9、es that was missing and modified the Makefile by adding the right location for those librariesLearn how tclbuild a driver for many different cards, especially video cards, in a Kernel on Linux distribution 2.6Learn how to dissect the long source code(>65 pages with more than 3700 lines of codes)L

10、earn how to debug subtle errorsImprove how to use the following techniques Char Device driver Memory mapped I/O Internal mutual exclusion (spinlocks and semaphores) Use of lOCUs Interrupt & Timer management (tasklets and kernel timer API) Learn more about Linux like making a make file, etc.Improve knowledge about LinuxWorks left The color display for different resolutions still needs to be done To work