usb_reset_and_verify_device(9)

✨ usb_reset_and_verify_device(9) — Kernel API Manual ✨

Okay so bestie, welcome to the usb_reset_and_verify_device(9) page. This is the iconic little routine that does a USB port reset to reinitialize a device. It's giving "main character energy" for when your USB thing is acting up and you need it to remember how to be a device again. No cap.

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🌸 SYNOPSIS 🌸

int usb_reset_and_verify_device (struct usb_device *udev );

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🎀 ARGUMENTS 🎀

• udev — the device you wanna reset. Lowkey important: it must not be in SUSPENDED or NOTATTACHED state. Like, it has to actually be awake and attached, otherwise this is not the vibe.

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💅 DESCRIPTION 💅

⚠️ WARNING — do not use this routine to reset a composite device (one with multiple interfaces owned by separate drivers)! Use usb_reset_device instead. I'm literally begging you. This is the one rule. Periodt.

So what does it actually do? It does a port reset, reassigns the device's address, and establishes its former operating configuration. Slay.

But here's the tea: if the reset fails, or the device's descriptors change from their values before the reset, or the original configuration and altsettings cannot be restored — then a flag gets set telling hub_wq to pretend the device has been disconnected and then re-connected. All drivers will be unbound, and the device will be re-enumerated and probed all over again. It's giving "we're starting from scratch, bestie." 😭

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🔥 RETURN 🔥

• 0 — the reset succeeded. Iconic. We love to see it. 🎉
• -ENODEV — the device has been flagged for logical disconnection. It's not you, it's the flag.
• some other negative error code — the reset wasn't even attempted. Rude, but okay.

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👑 NOTE 👑

The caller must own the device lock and the port lock. The latter is taken by usb_reset_device. For example, it's safe to use usb_reset_device from a driver probe routine after downloading new firmware. For calls that might not occur during probe, drivers should lock the device using usb_lock_device_for_reset. Locking tea ☕ — don't skip it.

Locking exception: This routine may also be called from within an autoresume handler. Such usage won't conflict with other tasks holding the device lock because these tasks should always call usb_autopm_resume_device, thereby preventing any unwanted autoresume. The autoresume handler is expected to have already acquired the port lock before calling this routine. So like, it's a special case but it's handled. You're fine. Probably. 💜

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🦋 SEE ALSO 🦋

Kernel file ./drivers/usb/core/hub.c

• usb_hub_set_port_power(9)
• usb_hub_clear_tt_buffer(9)
• usb_remove_device(9)
• usb_set_device_state(9)
• usb_disconnect(9)
• usb_enumerate_device_otg(9)
• usb_enumerate_device(9)
• usb_new_device(9)
• usb_deauthorize_device(9)
• get_port_ssp_rate(9)
• usb_root_hub_lost_power(9)
• hub_hc_release_resources(9)
• usb_reset_device(9)
• usb_queue_reset_device(9)
• usb_hub_find_child(9)
• usb_get_hub_port_acpi_handle(9)

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So that's the whole page, bestie. This gem lives in ./drivers/usb/core and the manual is dated October 2026. Go forth and reset responsibly. No cap, you got this. 💖✨