Bug#933174: wayland: Brightness bar not displayed when adjusting screen brightness

[Conrad Hughes <debbugs@xrad.org>]

Sorry for the slow reply.  The laptop is an old (2012) Sony Vaio; I
attach the output of lspci and lshw below.

Conrad

lspci:
  00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)

lshw:
  *-display
    description: VGA compatible controller
    product: 3rd Gen Core processor Graphics Controller
    vendor: Intel Corporation
    physical id: 2
    bus info: pci@0000:00:02.0
    version: 09
    width: 64 bits
    clock: 33MHz
    capabilities: vga_controller bus_master cap_list rom
    configuration: driver=i915 latency=0
    resources: irq:28 memory:d7000000-d73fffff memory:c0000000-cfffffff ioport:9000(size=64) memory:c0000-dffff
    *-usb:0
    description: USB controller
    product: 7 Series/C210 Series Chipset Family USB xHCI Host Controller
    vendor: Intel Corporation
    physical id: 14
    bus info: pci@0000:00:14.0
    version: 04
    width: 64 bits
    clock: 33MHz
    capabilities: xhci bus_master cap_list
    configuration: driver=xhci_hcd latency=0
    resources: irq:27 memory:d7400000-d740ffff