tag 81532 notabug close 81523 stop closing here as grub is not part of GNU coreutils.
I suggest you resend to <[email protected]> cheers, Padraig On 01/08/2026 10:05, GC via GNU coreutils Bug Reports wrote:
Subject: Bug: Lack of software debouncing / polling rate limit causes interrupt lockup in CSM/BIOS mode on AMD B550 Hello GRUB Developers, I am reporting a severe input issue when running GRUB2 in legacy BIOS/CSM mode on certain AMD B550 platforms (specifically the MSI MAG B550 Tomahawk / in contrast MSI B550 MPG works fine). When using standard USB wired keyboards via the BIOS emulation layer, GRUB experiences an extreme key bounce effect (every keypress is registered 5-20 times). If a navigation key (like Arrow Down) is held down, the entire system locks up instantly. The CPU core goes into a hard lockup/busy-loop (power draw increases by 30W, fans spin up). I have tried forcing `GRUB_TERMINAL_INPUT="at_keyboard"`, but the issue persists. It seems the BIOS emulated keyboard driver fires interrupts at an unthrottled rate, and GRUB's real-mode/protected-mode input handler has no built-in software debouncing or polling-rate limitation to reject these rapid duplicate packets. Would it be possible to implement a basic input dumper/debouncer or a slight delay loop inside the legacy keyboard polling routine to prevent such hardware interrupt storms from freezing the bootloader? Best regards. (Mail was generated by gemini due to my bad English.)
