Skip to content
  • Anssi Hannula's avatar
    HID: fix a lockup regression when using force feedback on a PID device · f129ea6d
    Anssi Hannula authored
    Commit 8006479c
    
     introduced a spinlock in
    input_dev->event_lock, which is locked when handling input events.
    However, the hid-pidff driver sleeps when handling events as it waits for
    reports being sent to the device before changing the report contents
    again.
    This causes a system lockup when trying to use force feedback with a PID
    device, a regression introduced in 2.6.24 and 2.6.23.15.
    
    Fix it by extracting the raw report data from struct hid_report
    immediately when hid_submit_report() is called, therefore allowing
    drivers to change the contents of struct hid_report immediately without
    affecting the already-queued transfer.
    
    In hid-pidff, re-add the removed usbhid_wait_io() to
    pidff_erase_effect() instead, to prevent a full report queue from causing
    the submission to fail, thus not freeing up device memory.
    pidff_erase_effect() is not called while dev->event_lock is held.
    
    Signed-off-by: default avatarAnssi Hannula <anssi.hannula@gmail.com>
    Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
    f129ea6d