我刚刚购买了带有 AMD Radeon RX 550M 显卡的新笔记本电脑，安装了全新的 Fedora 27，一切运行正常。
但...
更新（dnf update）并重启笔记本电脑后，我的 HDMI 停止工作。我没有手动安装任何驱动程序。您是否对可能出现的问题有任何建议？我提供lspci并xrandr输出：
lspci
00:00.0 Host bridge: Intel Corporation Device 5914 (rev 08)
00:02.0 VGA compatible controller: Intel Corporation Device 5917 (rev 07)
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21)
00:15.0 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #0 (rev 21)
00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI #1 (rev 21)
00:17.0 SATA controller: Intel Corporation Sunrise Point-LP SATA Controller [AHCI mode] (rev 21)
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #1 (rev f1)
00:1c.4 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #5 (rev f1)
00:1d.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #9 (rev f1)
00:1d.1 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #10 (rev f1)
00:1d.2 PCI bridge: Intel Corporation Device 9d1a (rev f1)
00:1f.0 ISA bridge: Intel Corporation Device 9d4e (rev 21)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21)
00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev 21)
00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21)
01:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Lexa PRO [Radeon RX 550] (rev c0)
02:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM961/PM961
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
04:00.0 Network controller: Intel Corporation Dual Band Wireless-AC 3165 Plus Bluetooth (rev 99)
05:00.0 SD Host controller: O2 Micro, Inc. SD/MMC Card Reader Controller (rev 01)
xrandr -q
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
XWAYLAND0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 340mm x 190mm
1920x1080 59.96*+
值得一提的是：我在传统支持模式（非 UEFI）下运行 BIOS，选择的是显卡discrete。