i915_gem_wait_ioctl(9)

💫 i915_gem_wait_ioctl(9) 💫

okay so bestie, this is the manual page for i915_gem_wait_ioctl — it's literally the function that implements DRM_IOCTL_I915_GEM_WAIT, and we're gonna get into it. no cap, it's iconic in a "quietly doing GPU wait stuff" kinda way. 💅

🎀 SYNOPSIS 🎀

int i915_gem_wait_ioctl (struct drm_device *dev , void *data , struct
       drm_file *file );

✨ ARGUMENTS ✨

• dev — the drm device pointer, aka the main character of your GPU world. 🖥️
• data — the ioctl data blob. it's giving "mystery payload" but in a fun way. 🫶
• file — the drm file pointer. which file? the drm one, babes. 📁

💖 DESCRIPTION 💖

So here's the tea, bestie: this function returns 0 if everything's slay, and if not, it throws an error and leaves the remaining time in the timeout parameter. let's break down the error codes, because there are... a few:

• -ETIME — the object is still busy after timeout. like, it literally didn't finish in time, rude. 😭
• -ERESTARTSYS — a signal interrupted the wait. so dramatic, honestly. ⚡
• -ENONENT — the object doesn't exist. gone. not invited to the party. 💀
• -EAGAIN — incomplete, restart syscall. also possible but rare, so don't stress unless it happens. 🔄
• -ENOMEM — "damn" is the official technical term for this one. memory said no. 💸
• -ENODEV — internal IRQ fail. the hardware is having a moment. 🙈
• -E? — the add request failed. the ? is doing a lot of heavy lifting, iykyk. 🤷‍♀️

now for the important part, so listen up: the wait ioctl with a timeout of 0 reimplements the busy ioctl. with any non-zero timeout parameter, the wait ioctl will wait for the given number of nanoseconds on an object becoming unbusy. but here's the plot twist — since the wait occurs without holding a global or exclusive lock, the object may become re-busied before this function completes. a similar but shorter race condition exists in the busy ioctl. so yeah, that's a whole vibe. not a bug exactly, just... the situation. 🚩

🦋 SEE ALSO 🦋

• Kernel file ./drivers/gpu/drm/i915/gem/i915_gem_wait.c — the source, the origin story, the blueprint. 📜
• i915_gem_object_wait(9) — related function, go check it out. 👀
• i915_gem_object_wait_migration(9) — migration-flavored waiting, also valid. 🚚

and that's the whole page, bestie! this icon came from ./drivers/gpu/drm/i915/gem and it's dated October 2026, version i915_gem_wait_ioctl(9). love that for us. now go forth and wait on objects responsibly! 👑💖✨