From: Hans de Goede <hdegoede@xxxxxxxxxx> [ Upstream commit b1884583fcd17d6a1b1bba94bbb5826e6b5c6e17 ] The i8042 module exports several symbols which may be used by other modules. Before this commit it would refuse to load (when built as a module itself) on systems without an i8042 controller. This is a problem specifically for the asus-nb-wmi module. Many Asus laptops support the Asus WMI interface. Some of them have an i8042 controller and need to use i8042_install_filter() to filter some kbd events. Other models do not have an i8042 controller (e.g. they use an USB attached kbd). Before this commit the asus-nb-wmi driver could not be loaded on Asus models without an i8042 controller, when the i8042 code was built as a module (as Arch Linux does) because the module_init function of the i8042 module would fail with -ENODEV and thus the i8042_install_filter symbol could not be loaded. This commit fixes this by exiting from module_init with a return code of 0 if no controller is found. It also adds a i8042_present bool to make the module_exit function a no-op in this case and also adds a check for i8042_present to the exported i8042_command function. The latter i8042_present check should not really be necessary because when builtin that function can already be used on systems without an i8042 controller, but better safe then sorry. Reported-and-tested-by: Marius Iacob <themariusus@xxxxxxxxx> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Link: https://lore.kernel.org/r/20201008112628.3979-2-hdegoede@xxxxxxxxxx Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/input/serio/i8042.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c index c84c685056b99..6b648339733fa 100644 --- a/drivers/input/serio/i8042.c +++ b/drivers/input/serio/i8042.c @@ -125,6 +125,7 @@ module_param_named(unmask_kbd_data, i8042_unmask_kbd_data, bool, 0600); MODULE_PARM_DESC(unmask_kbd_data, "Unconditional enable (may reveal sensitive data) of normally sanitize-filtered kbd data traffic debug log [pre-condition: i8042.debug=1 enabled]"); #endif +static bool i8042_present; static bool i8042_bypass_aux_irq_test; static char i8042_kbd_firmware_id[128]; static char i8042_aux_firmware_id[128]; @@ -343,6 +344,9 @@ int i8042_command(unsigned char *param, int command) unsigned long flags; int retval; + if (!i8042_present) + return -1; + spin_lock_irqsave(&i8042_lock, flags); retval = __i8042_command(param, command); spin_unlock_irqrestore(&i8042_lock, flags); @@ -1597,12 +1601,15 @@ static int __init i8042_init(void) err = i8042_platform_init(); if (err) - return err; + return (err == -ENODEV) ? 0 : err; err = i8042_controller_check(); if (err) goto err_platform_exit; + /* Set this before creating the dev to allow i8042_command to work right away */ + i8042_present = true; + pdev = platform_create_bundle(&i8042_driver, i8042_probe, NULL, 0, NULL, 0); if (IS_ERR(pdev)) { err = PTR_ERR(pdev); @@ -1621,6 +1628,9 @@ static int __init i8042_init(void) static void __exit i8042_exit(void) { + if (!i8042_present) + return; + platform_device_unregister(i8042_platform_device); platform_driver_unregister(&i8042_driver); i8042_platform_exit(); -- 2.27.0
