Bug 24427

Summary:	nouveau power management not working on kernel > 4.14.70
Product:	Mageia	Reporter:	Martin Whitaker <mageia>
Component:	RPM Packages	Assignee:	Kernel and Drivers maintainers <kernel>
Status:	RESOLVED WORKSFORME	QA Contact:
Severity:	normal
Priority:	Normal	CC:	marja11
Version:	6
Target Milestone:	---
Hardware:	All
OS:	Linux
Whiteboard:
Source RPM:	kernel-4.14.78-1.mga6 .. kernel-4.14.100-1.mga6	CVE:
Status comment:

Description Martin Whitaker 2019-02-25 19:03:01 CET

I have a laptop with hybrid Intel/NVIDIA graphics. I configure X to use the intel driver only. /sys/kernel/debug/vgaswitcheroo/switch shows

0:IGD:+:Pwr:0000:00:02.0
1:DIS: :DynPwr:0000:01:00.0

With kernel 4.14.70 and earlier, the NVIDIA GPU is automatically powered down. Starting with kernel 4.14.78, the NVIDIA GPU remains powered on, causing the laptop to run very hot (it doesn't really have adequate cooling for that GPU).

I have tried booting with nouveau.runpm=0. Then /sys/kernel/debug/vgaswitcheroo/switch shows

0:IGD:+:Pwr:0000:00:02.0
1:DIS: :Pwr:0000:01:00.0

"echo OFF > /sys/kernel/debug/vgaswitcheroo/switch" changes that to

0:IGD:+:Pwr:0000:00:02.0
1:DIS: :Off:0000:01:00.0

but powertop (and the laptop temperature) shows the card is still powered on.

% lspci -nn
00:00.0 Host bridge [0600]: Intel Corporation 3rd Gen Core processor DRAM Controller [8086:0154] (rev 09)
00:01.0 PCI bridge [0604]: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port [8086:0151] (rev 09)
00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)
00:14.0 USB controller [0c03]: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller [8086:1e31] (rev 04)
00:16.0 Communication controller [0780]: Intel Corporation 7 Series/C216 Chipset Family MEI Controller #1 [8086:1e3a] (rev 04)
00:1a.0 USB controller [0c03]: Intel Corporation 7 Series/C216 Chipset Family USB Enhanced Host Controller #2 [8086:1e2d] (rev 04)
00:1b.0 Audio device [0403]: Intel Corporation 7 Series/C216 Chipset Family High Definition Audio Controller [8086:1e20] (rev 04)
00:1c.0 PCI bridge [0604]: Intel Corporation 7 Series/C216 Chipset Family PCI Express Root Port 1 [8086:1e10] (rev c4)
00:1c.1 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 2 [8086:1e12] (rev c4)
00:1c.3 PCI bridge [0604]: Intel Corporation 7 Series/C216 Chipset Family PCI Express Root Port 4 [8086:1e16] (rev c4)
00:1c.5 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 6 [8086:1e1a] (rev c4)
00:1d.0 USB controller [0c03]: Intel Corporation 7 Series/C216 Chipset Family USB Enhanced Host Controller #1 [8086:1e26] (rev 04)
00:1f.0 ISA bridge [0601]: Intel Corporation HM77 Express Chipset LPC Controller [8086:1e57] (rev 04)
00:1f.2 RAID bus controller [0104]: Intel Corporation 82801 Mobile SATA Controller [RAID mode] [8086:282a] (rev 04)
00:1f.3 SMBus [0c05]: Intel Corporation 7 Series/C216 Chipset Family SMBus Controller [8086:1e22] (rev 04)
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GF108M [GeForce GT 635M] [10de:0de3] (rev a1)
08:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5229 PCI Express Card Reader [10ec:5229] (rev 01)
0a:00.0 Network controller [0280]: Intel Corporation Centrino Wireless-N 2230 [8086:0887] (rev c4)
0b:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 07)

Comment 1 Martin Whitaker 2019-02-25 21:10:23 CET

Seems this one is intermittent - I can't reproduce it now after testing 4.14.103, but I went back and forth multiple times earlier with consistent results, and I've been noticing the overheating for a while now. I'll leave it for a bit to see if the fault reappears.

Marja Van Waes 2019-02-26 13:39:58 CET

Assignee: bugsquad => kernel
CC: (none) => marja11

Comment 2 Martin Whitaker 2020-06-06 18:31:51 CEST

There's a workaround for this. After the system has booted, unloading and reloading the nouveau kernel module allows power management to start working.

Not ideal, but works for me.

Status: NEW => RESOLVED
Resolution: (none) => WORKSFORME