linux-device-driver

问题 I am working on Linux UEFI .I want to access the efi variables through my driver code. Currently I'm looking linux/efi.h API like efi.get_variable(). but I'm not getting how to call those APIs with from my driver code. struct efi efi1; efi_init(); efi_char16_t *name = (efi_char16_t *)"Boot001"; efi_guid_t *vendor = (efi_guid_t *)"8be4df61-93ca-11d2-aa0d-00e098032b8c"; u32 *attr = (u32 *)0x7; unsigned long data_size = 1024; void *data = NULL; printk("\n Showing efi info \n"); stat = efi1.get

问题 I am working on Linux UEFI .I want to access the efi variables through my driver code. Currently I'm looking linux/efi.h API like efi.get_variable(). but I'm not getting how to call those APIs with from my driver code. struct efi efi1; efi_init(); efi_char16_t *name = (efi_char16_t *)"Boot001"; efi_guid_t *vendor = (efi_guid_t *)"8be4df61-93ca-11d2-aa0d-00e098032b8c"; u32 *attr = (u32 *)0x7; unsigned long data_size = 1024; void *data = NULL; printk("\n Showing efi info \n"); stat = efi1.get

问题 As per my understanding chosen node is used to send boot arguments to the kernel. The following is the chosen node of the existing device code (am335x-bone-common.dtsi). chosen { stdout-path = &uart0; }; So, I have modified chosen node to pass kernel arguments. chosen { bootargs = "console=ttyO0,115200 root=/dev/mmcblk0p2 rootfstype=ext3 rw rootwait"; stdout-path = &uart0; }; While bringing up the board I encountered KERNEL PANIC, Here is the log {https://pastebin.com/XHyrsmfG} FYI: These are

问题 I written my ISR and my tasklet ran immediately. BUT , I have seen people saying that tasklet runs only when it gets CPU attention. This is a very generic term CPU attention so i recite for those responders. I mean exactly which moment cpu attention goes to tasklet execution and what happen to the state of CPU ? Secondly, if suppose that i am keep on getting hard interrupt then when will tasklet get chance to run? Is it possible that tasklet may not get chance to run? How does kernel take

问题 I hope to find some help even if this issue might be more hardware than software related (we'll see). I'm working on a custom board based on Freescales P1021 processor (ppc, e500v2 core). A external PCB will be connected and could be configured by SPI. The specifications of this external PCB reads as it expects a 2-byte command in full duplex mode and that only the last byte is used to transfer data back on MISO. Knowing this i currently work to prepare some pieces of software to test this

问题 Is it possible to expand the ioctl interface in Linux so that the user-space application can send a pointer to a function to the kernel space driver? I'm in particular thinking of ways to handle the stream in user-controllable way but doing it in the kernel. Those operations could be attached to the kernel module but this would make development a lot easier as I wouldn't need to mess with the kernel during development. More specifically, this would be the process: Data is read by the driver

问题 I'm trying to compile a simple hello world module following this guide and I'm confused about what the Makefile is actually doing. obj-m += hello-1.o all: make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules clean: make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean I understand that when i type the make command it will run the all recipe which runs make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules . So now it runs the Makefile found at the path given after the -C

问题 I'd like to boot the raspberry pi with a device-tree-driven linux kernel, is there anything special to do to do that? Can anyone point what are required to set up a device-tree-based kernel boot up for the raspberry pi. I may need to have raspberry pi kernel source where drivers for devices should be compatible with device tree. If so, where can I find such kernel sources for Raspberry Pi? 回答1: Device-Tree support on Raspberry Pi Raspberry Pi embeds an ARM11 SoC: Broadcom BCM2835. Device Tree

问题 I am having trouble placing firmware properly on an Android device, I keep getting: <3>[ 3590.997375] usb 3-1.4: ath9k_htc: Firmware - htc_7010.fw not found If on a standard linux machine running Ubuntu, I place htc_7010.fw in /lib/firmware then I do not get this error. However, if I place this firmware in /lib/firmware on Android, I still get the error. I have tried all of the following directories and still receive the error: /lib/firmware /etc/firmware /system/lib/modules /system/lib

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . I am programming linux device driver over a very slow interface, whose ping round time can be as long as several minutes. When I try to use TCP to establish connection between two nodes the connection always times out. Is there a method to set the TCP retransmission or handshaking timeout longer in the driver,