uclogic_params_get_str_desc(9)

📦 version 7.3.1, in nixpkgs unstable

💖 uclogic_params_get_str_desc(9) — a Kernel API Manual moment ✨

okay bestie, so this is a page from the Kernel API Manual and it's lowkey one of those little helper functions that does exactly one thing and does it slayfully: it goes and grabs a string descriptor off a HID device interface and drops it into a kmalloc-allocated buffer as is — like, no character encoding conversion, none, zero, we're not touching the bytes, periodt 🎀

🌸 NAME 🌸

uclogic_params_get_str_desc — retrieve a string descriptor from a HID device interface, putting it into a kmalloc-allocated buffer as is, without character encoding conversion. raw bytes stay raw, iykyk 💅

✨ SYNOPSIS ✨

int uclogic_params_get_str_desc (__u8 **pbuf , struct hid_device *hdev ,
__u8 idx , size_t len );

🦋 ARGUMENTS 🦋

  • pbuf — the location where the pointer to the kmalloc-allocated buffer goes. that buffer is the one holding the retrieved descriptor, bestie. it is not modified in case of error (so don't go reading a stale pointer, okay? 🙈). and yes, it can be NULL — do that if you literally want the retrieved descriptor just… discarded. no thoughts, head empty, bye bytes 💀
  • hdev — the HID device of the tablet interface we're retrieving the string descriptor from. cannot be NULL. like, that's the whole vibe, no device no descriptor, fr fr 🫶
  • idx — the index of the string descriptor to request from the device. which one? that one. the one at idx ⭐
  • len — the length of the buffer to allocate and the amount of data to retrieve. two jobs, one argument, main character energy 👑

🔥 RETURN 🔥

so here's the vibe check on what comes back:

  • the number of bytes retrieved (<= len) 🎀
  • -EPIPE if the descriptor was not found 😭 (not found bestie, it's giving empty drawer)
  • or another negative errno code in case of some other error 💀

🌈 SEE ALSO 🌈

the kernel file lives right here, iconic:

Kernel file ./drivers/hid/hid-uclogic-params.c

and here's the whole friend group, all of them, no one left behind 🫶:

🧚 quick reminder bestie: pbuf stays untouched on error, and hdev can never be NULL. those two are the ones that will bite you if you forget them 💅

and that's the page!! shipped from ./drivers/hid, dated October 2026, in the Kernel API Manual 🦋💜 mwah, go read your descriptors responsibly ✨

📦 where this page comes from