chardev

问题 from my previsou question Why does module failed to load? (/dev/scull0 : no such device or address) I managed to load the module via /sbin/insmod , but after that, I have log out the dmesg: [ 2765.707018] scull: loading out-of-tree module taints kernel. [ 2765.707106] scull: module verification failed: signature and/or required key missing - tainting kernel [ 2765.707929] Passed scull_init_module at 41 (debug info - successful load of init module) [ 6027.843914] acer_wmi: Unknown function

问题 From my previous question: How to build external modules in ubuntu? I thought I cannot load module due to loading out-of-tree or tainting kernel , but to my scull_init_module (source below) I have added printk so I know I get loaded from kern log. But I did not (no output in the log -- the log is the same as from the link). uname -a == 4.19.0-9-amd64 #1 SMP Debian 4.19.118-2 (2020-04-29) x86_64 GNU/Linux (no use of ubuntu - as from the link). scull_init_module : #ifndef scull_major #define

问题 I'm trying to boost DMA<->CPU<->GPU data transfer by: 1. Mapping my (proprietary) device Linux Kernel allocated memory to user space 2. Registering the later (mapped memory) to Cuda with cudaHostRegister API function. While mapping User Space allocated memory mapped to my device DMA and then registered to Cuda with cudaHostRegister works just fine, trying to register "kmalloced" memory results in "Invalid Argument" error returned by cudaHostRegister. First I thought the problem was with