How to install firmware-linux-nonfree

Acer Aspire E15, running Jessie (latest).

At boot, it bleats: "drm:radeon_pci_probe] *ERROR* radeon kernel 
modesetting for R600 or later requires firmware-linux-nonfree" so I 
installed it with "apt-get install ...", but it made no difference.  What 
else needs to be done?

Also, the WiFi does not work on 5GHz; is there an update for that?  Output 
of "lsusb":

    Bus 002 Device 003: ID 06cb:2970 Synaptics, Inc. 
    Bus 002 Device 002: ID 0438:7900 Advanced Micro Devices, Inc. 
    Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
    Bus 001 Device 006: ID 04f2:b469 Chicony Electronics Co., Ltd 
    Bus 001 Device 005: ID 04ca:300b Lite-On Technology Corp. 
    Bus 001 Device 004: ID 2188:0ae1  
    Bus 001 Device 003: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T
    Bus 001 Device 002: ID 0438:7900 Advanced Micro Devices, Inc. 
    Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
    Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
    Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Thanks.