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    Input: synaptics - fix sync lost after resume on some laptops · eeb06558
    Eric Miao 提交于
    In summary, the symptom is intermittent key events lost after resume
    on some machines with synaptics touchpad (seems this is synaptics _only_),
    and key events loss is due to serio port reconnect after psmouse sync lost.
    Removing psmouse and inserting it back during the suspend/resume process
    is able to work around the issue, so the difference between psmouse_connect()
    and psmouse_reconnect() is the key to the root cause of this problem.
    
    After comparing the two different paths, synaptics driver has its own
    implementation of synaptics_reconnect(), and the missing psmouse_probe()
    seems significant, the patch below added psmouse_probe() to the reconnect
    process, and has been verified many times that the issue could not be reliably
    reproduced.
    
    There are two PS/2 commands in psmouse_probe():
    
      1. PSMOUSE_CMD_GETID
      2. PSMOUSE_CMD_RESET_DIS
    
    Only the PSMOUSE_CMD_GETID seems to be significant. The
    PSMOUSE_CMD_RESET_DIS is irrelevant to this issue after trying
    several times.  So we have only implemented this patch to issue
    the PSMOUSE_CMD_GETID so far.
    Tested-by: NDaniel Manrique <daniel.manrique@canonical.com>
    Signed-off-by: NJames M Leddy <james.leddy@canonical.com>
    Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
    eeb06558
synaptics.c 44.8 KB