STRUCT FWCTL_INFO(9)

💅 NAME 💅

okay so bestie, welcome to the Kernel API Manual ✨ — this page is all about struct fwctl_info, which is literally the struct you hand to ioctl(FWCTL_INFO). no cap, that's the whole vibe 🫶

🎀 SYNOPSIS 🎀

struct fwctl_info {
    __u32 size;
    __u32 flags;
    __u32 out_device_type;
    __u32 device_data_len;
    __aligned_u64 out_device_data;
 };

🌸 Members 🌸

• size — it's giving sizeof(struct fwctl_info). that's it, that's the field 💅
• flags — must be 0. not "should be", not "hey maybe", must. zero it out, periodt 🚫
• out_device_type — on the way out, this returns the type of the device, straight from enum fwctl_device_type. iykyk 👑
• device_data_len — on input, this is the length of the out_device_data memory. on output, it's the size of the kernel's device_data, which may be larger or smaller than the input 😭 — so check it! it can be 0 on input, bestie 💀
• out_device_data — a pointer to memory that's device_data_len bytes long. the kernel will fill the entire memory, zeroing as required. every byte accounted for, slay ✨

💖 Description 💖

so this ioctl returns the basic info about this here fwctl instance — most importantly, what driver is being used to define the device_data format. that's the main character detail you're here for 🌟

🦋 SEE ALSO 🦋

• the kernel file ./include/uapi/fwctl/fwctl.h (go read it, it's iconic)
• General ioctl format(9)
• enum fwctl_rpc_scope(9)
• struct fwctl_rpc(9)

and that's the page, bestie!! 🍓 this little beauty lives out of ./include/uapi/fwctl and it's stamped October 2026 — go forth and ioctl responsibly, mwah 💜🧚