linux-device-driver

问题 I've used UMLet to draw some UML diagrams describing various entity relationships for each of the chapters of Linux Device Drivers 3Ed (LDD3), by Corbet, Rubini, Kroah-Hartman. The latest version of the diagrams can be found here: Linux Device Drivers 3Ed UML Diagrams I would like to ask help understanding a scheduling problem which is supported by documentation in the Non-Blocking File IO Sequence Diagram(s) at the above link, and in LDD3 on P156-158, and in particular this code snippet from

问题 I getting a kernel crash as below. Here I can observe large memory is present in unevictablle page. I wish to know when exactly memory is added to unevictable page list. Also, from the below message I can understand only 1724kB is available in the system. is it correct? kswapd0: page allocation failure. order:0, mode:0xd0 [<c002aed4>] (unwind_backtrace+0x0/0xdc) from [<c006d5b0>] (__alloc_pages_nodemask+0x490/0x4ec) [<c006d5b0>] (__alloc_pages_nodemask+0x490/0x4ec) from [<c008416c>] (cache

问题 I getting a kernel crash as below. Here I can observe large memory is present in unevictablle page. I wish to know when exactly memory is added to unevictable page list. Also, from the below message I can understand only 1724kB is available in the system. is it correct? kswapd0: page allocation failure. order:0, mode:0xd0 [<c002aed4>] (unwind_backtrace+0x0/0xdc) from [<c006d5b0>] (__alloc_pages_nodemask+0x490/0x4ec) [<c006d5b0>] (__alloc_pages_nodemask+0x490/0x4ec) from [<c008416c>] (cache

问题 I am programming a kernel module in C which is struggling to access IRQ description array elements and to display all action names of these elements. At the beginning, I thought that this irq_desc array is sonething like a macro but after compiling i understood it is not. Then I used for_each_irq_desc(irq, desc) function. but this time it returned a warning: WARNING: "irq_to_desc" [/home/samet/Masaüstü/Assignment3/Ass-1.ko] undefined! and after this warning, i tried to insmod the module into

问题 I have gone through some driver implementation in Linux Kernel Source and can see that these are the platform driver. drivers/net/ethernet/smsc/smsc911x.c static struct platform_driver smc911x_driver = { .probe = smc911x_drv_probe, .remove = smc911x_drv_remove, .suspend = smc911x_drv_suspend, .resume = smc911x_drv_resume, .driver = { .name = CARDNAME, .owner = THIS_MODULE, }, }; Above is a driver for platform device(smsc based Ethernet controller) and platform devices are devices which are

问题 I have gone through some driver implementation in Linux Kernel Source and can see that these are the platform driver. drivers/net/ethernet/smsc/smsc911x.c static struct platform_driver smc911x_driver = { .probe = smc911x_drv_probe, .remove = smc911x_drv_remove, .suspend = smc911x_drv_suspend, .resume = smc911x_drv_resume, .driver = { .name = CARDNAME, .owner = THIS_MODULE, }, }; Above is a driver for platform device(smsc based Ethernet controller) and platform devices are devices which are

问题 What does the below comment mean in Intel Processor data sheet? How can I check that in my driver's code in Linux? If CPUID.06H:EAX.[7] = 1 I come across this type of statements in the SW developer's manual for Intel Processors in the comments column in register description table.. Ref: https://software.intel.com/sites/default/files/managed/22/0d/335592-sdm-vol-4.pdf Please help me to understand the processor descriptions. Thanks. 回答1: CPUID.06H:EAX.[7] enables the discovery of the HWP

问题 I was writing a console driver for linux and I came across the tty interface that I need to set up for this driver. I got confused as to how tty drivers are bound with low-level drivers. Many times the root file system already contains a lot of tty devices. I am wondering how low-level devices can bind to one of the existing tty nodes on the root file system. For example, /dev/tty7 : Node on the root file system. How does a low-level device driver connect with this node? Or should that low

问题 i'd need to obtain a pointer to a particular device registered in linux. Briefly, this device represents a mii_bus object. The problem is that this device seems doesn't belong to a bus (its dev->bus is NULL ) so i can't use for example the function bus_for_each_dev . The device is however registered by the Open Firmware layer and i can see the relative of_device (which is the parent of the device i'm interested in) in /sys/bus/of_platform . My device is also registered in a class so i can

问题 Existing kernel drivers such as xilinx have specific way to be registered (as tty device), if they are mapped directly to cpu memory map as done here with device tree: https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18842249/Uartlite+Driver But in other cases, there is a PCIe device (like FPGA which has the xilinx uart IPs) which is connected to and the cpu. How should we make the uart get registered when using PCIe device ? The device tree I try to register into PCIe is uartlite driver