HID: nintendo: fix rumble starved by the input report cadence gate

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Rumble on third-party controllers speaking the Switch protocol is weak
and intermittent over bluetooth, and absent on some units.

Since commit d750d14803 ("HID: nintendo: fix rumble rate limiter"),
joycon_enforce_subcmd_rate() requires JC_SUBCMD_VALID_DELTA_REQ (3)
consecutive input reports spaced 8-17ms apart before releasing a
subcommand. That window is the official Pro Controller's bluetooth
cadence, and controllers that do not report on it cannot pass the gate,
so their rumble is starved.

Measured over bluetooth on one host, reading the controller directly,
fraction of reports at which the requirement is met:

  official Pro Controller     95%
  Datafrog clone              46-52%
  8BitDo Pro 2                2.5-4%

The Pro 2 delivers reports in pairs, so 11-19% of its deltas are 0ms and
reset the counter. Affected controllers report Nintendo's USB IDs, and
the MAC is no better: the Datafrog clone reports an OUI registered to
Nintendo, so identifying them by vendor would misclassify it.

Instead, notice when the requirement cannot be met: after
JC_SUBCMD_RATE_MAX_FAILURES exhaustions of the limiter, fall back to the
pre-d750d1480362 throttle, which keeps the 25ms spacing and the
transmit-after-receive synchronisation from commit e93363f716 ("HID:
nintendo: ratelimit subcommands and rumble") and drops only the cadence
requirement. Exhaustions are counted cumulatively, as an affected
controller meets the requirement occasionally and a consecutive count
would never be reached.

Signed-off-by: Alexandre Derumier <aderumier@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

...

This commit is contained in:

Alexandre Derumier 2026-08-01 11:00:59 +02:00 • committed by Jiri Kosina

parent 1f9b25d3fb

commit 781f8e020a

1 changed files with 38 additions and 1 deletions

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drivers/hid/hid-nintendo.c

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