Commit 181135b
usb: add NO_LPM quirk for Realforce 87U Keyboard
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: [email protected]
Signed-off-by: Nicolas Dumazet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>1 parent 9d5333c commit 181135b
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