Hello Michał Kępień,
The patch 819cddae7cfa: "platform/x86: fujitsu-laptop: Clean up
constants" from Feb 20, 2018, leads to the following static checker
warning:
drivers/platform/x86/fujitsu-laptop.c:763 acpi_fujitsu_laptop_leds_register()
warn: always true condition '(call_fext_func(device, ((1 << (12)) | (1 << (0))), 2, (1 << (16)), 0) != (1 << (31))) => (s32min-s32max != 2147483648)'
drivers/platform/x86/fujitsu-laptop.c:816 acpi_fujitsu_laptop_add()
warn: impossible condition '(priv->flags_supported == (1 << (31))) => (0-2147483647,18446744071562067968-u64max == 2147483648)'
drivers/platform/x86/fujitsu-laptop.c
756 /* Support for eco led is not always signaled in bit corresponding
757 * to the bit used to control the led. According to the DSDT table,
758 * bit 14 seems to indicate presence of said led as well.
759 * Confirm by testing the status.
760 */
761 if ((call_fext_func(device, FUNC_LEDS, 0x0, 0x0, 0x0) & BIT(14)) &&
762 (call_fext_func(device,
763 FUNC_LEDS, 0x2, ECO_LED, 0x0) != UNSUPPORTED_CMD)) {
^^^^^^^^^^^^^^^^^^
The problem is that before UNSUPPORTED_CMD was 0x80000000 (int) but now
it's BIT(31) (unsigned long). call_fext_func() returns an int so if
it returns 0x80000000 and that gets type promoted to unsigned long on
a 64 bit system then the sign gets extended and it becomes
0xffffffff80000000. 0xffffffff80000000 is not equal to 0x80000000 so
this condition is always true.
764 led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
765 if (!led)
766 return -ENOMEM;
767
768 led->name = "fujitsu::eco_led";
769 led->brightness_set_blocking = eco_led_set;
770 led->brightness_get = eco_led_get;
771 ret = devm_led_classdev_register(&device->dev, led);
772 if (ret)
773 return ret;
774 }
775
776 return 0;
777 }
778
779 static int acpi_fujitsu_laptop_add(struct acpi_device *device)
780 {
781 struct fujitsu_laptop *priv;
782 int ret, i = 0;
783
784 priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
785 if (!priv)
786 return -ENOMEM;
787
788 WARN_ONCE(fext, "More than one FUJ02E3 ACPI device was found. Driver may not work as intended.");
789 fext = device;
790
791 strcpy(acpi_device_name(device), ACPI_FUJITSU_LAPTOP_DEVICE_NAME);
792 strcpy(acpi_device_class(device), ACPI_FUJITSU_CLASS);
793 device->driver_data = priv;
794
795 /* kfifo */
796 spin_lock_init(&priv->fifo_lock);
797 ret = kfifo_alloc(&priv->fifo, RINGBUFFERSIZE * sizeof(int),
798 GFP_KERNEL);
799 if (ret)
800 return ret;
801
802 pr_info("ACPI: %s [%s]\n",
803 acpi_device_name(device), acpi_device_bid(device));
804
805 while (call_fext_func(device, FUNC_BUTTONS, 0x1, 0x0, 0x0) != 0 &&
806 i++ < MAX_HOTKEY_RINGBUFFER_SIZE)
807 ; /* No action, result is discarded */
808 acpi_handle_debug(device->handle, "Discarded %i ringbuffer entries\n",
809 i);
810
811 priv->flags_supported = call_fext_func(device, FUNC_FLAGS, 0x0, 0x0,
812 0x0);
813
814 /* Make sure our bitmask of supported functions is cleared if the
815 RFKILL function block is not implemented, like on the S7020. */
816 if (priv->flags_supported == UNSUPPORTED_CMD)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Same but always false.
817 priv->flags_supported = 0;
818
819 if (priv->flags_supported)
820 priv->flags_state = call_fext_func(device, FUNC_FLAGS, 0x4, 0x0,
821 0x0);
regards,
dan carpenter
