Commit b87527bd authored Nov 09, 2022 by Nicolas Dumazet Committed by Greg Kroah-Hartman Nov 25, 2022

usb: add NO_LPM quirk for Realforce 87U Keyboard

commit 181135bb20dcb184edd89817831b888eb8132741 upstream.

Before adding this quirk, this (mechanical keyboard) device would not be
recognized, logging:

  new full-speed USB device number 56 using xhci_hcd
  unable to read config index 0 descriptor/start: -32
  chopping to 0 config(s)

It would take dozens of plugging/unpuggling cycles for the keyboard to
be recognized. Keyboard seems to simply work after applying this quirk.

This issue had been reported by users in two places already ([1], [2])
but nobody tried upstreaming a patch yet. After testing I believe their
suggested fix (DELAY_INIT + NO_LPM + DEVICE_QUALIFIER) was probably a
little overkill. I assume this particular combination was tested because
it had been previously suggested in [3], but only NO_LPM seems
sufficient for this device.

[1]: https://qiita.com/float168/items/fed43d540c8e2201b543
[2]: https://blog.kostic.dev/posts/making-the-realforce-87ub-work-with-usb30-on-Ubuntu/
[3]: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1678477



Cc: stable@vger.kernel.org
Signed-off-by: Nicolas Dumazet <ndumazet@google.com>
Link: https://lore.kernel.org/r/20221109122946.706036-1-ndumazet@google.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent d6de1cfc

drivers/usb/core/quirks.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -362,6 +362,9 @@ static const struct usb_device_id usb_quirk_list[] = {
		{ USB_DEVICE(0x0781, 0x5583), .driver_info = USB_QUIRK_NO_LPM },
		{ USB_DEVICE(0x0781, 0x5591), .driver_info = USB_QUIRK_NO_LPM },

		/* Realforce 87U Keyboard */
		{ USB_DEVICE(0x0853, 0x011b), .driver_info = USB_QUIRK_NO_LPM },

		/* M-Systems Flash Disk Pioneers */
		{ USB_DEVICE(0x08ec, 0x1000), .driver_info = USB_QUIRK_RESET_RESUME },