https://bugzilla.kernel.org/show_bug.cgi?id=199047

Bug ID: 199047 Summary: [amdgpu CARRIZO] disabled backlight after S3 resume Product: Drivers Version: 2.5 Kernel Version: 4.16-rc1 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@kernel-bugs.osdl.org Reporter: johannes.hirte@datenkhaos.de Regression: No

After S3 resume, the backlight stays disabled. Re-enabling is possible with brightness-hotkeys. The regression was introduced with:

commit 4ec6ecf48c64d1da82a008f6fb0be86c4044287d (refs/bisect/bad) Author: Alex Deucher alexander.deucher@amd.com Date: Tue Dec 12 15:20:22 2017 -0500

drm/amdgpu: drop scratch regs save and restore from S3/S4 handling

The expectation is that the base driver doesn't mess with these. Some components interact with these directly so let the components handle these directly.

Reviewed-by: Harry Wentland harry.wentland@amd.com Acked-by: Christian König christian.koenig@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com

lspci:

00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1576 00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Device 1577 00:01.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Carrizo (rev c5) 00:01.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Kabini HDMI/DP Audio 00:02.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 157b 00:02.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 157c 00:02.3 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 157c 00:02.5 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 157c 00:03.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 157b 00:08.0 Encryption controller: Advanced Micro Devices, Inc. [AMD] Device 1578 00:09.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 157d 00:09.2 Audio device: Advanced Micro Devices, Inc. [AMD] Device 157a 00:10.0 USB controller: Advanced Micro Devices, Inc. [AMD] FCH USB XHCI Controller (rev 20) 00:11.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] (rev 49) 00:12.0 USB controller: Advanced Micro Devices, Inc. [AMD] FCH USB EHCI Controller (rev 49) 00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 4a) 00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge (rev 11) 00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1570 00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1571 00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1572 00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1573 00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1574 00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 1575 01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15) 02:00.0 Network controller: Intel Corporation Wireless 8260 (rev 3a) 03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS522A PCI Express Card Reader (rev 01)