Bug 105433

Summary: Unreliable Modesetting on Tonga with two DVI Screens
Product: DRI Reporter: Thomas R. <freedesktop-bugs>
Component: DRM/AMDgpuAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact:
Severity: normal    
Priority: medium CC: harry.wentland, nicholas.kazlauskas
Version: DRI git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
dmesg of boot, start of X and xrandr
none
dmesg of boot, start of X, xrandr with current staging
none
Kernel log with debug of 4.19.20+ before patch, including screen reset to get it to work
none
Kernel log with debug of 4.19.20+ after patch, including screen reset that does nothing none

Description Thomas R. 2018-03-10 23:31:52 UTC
Two devices connected via DVI, one not coming up (powersave, no signal). On retry , they may swap their working state, or both go to energy save, or rarely, both work. This happens regardless of resolutions set on the screens in question.

Screens: 2 x Benq G2222HDL
Connected via DVI (both straight to card)

Card: ASUS Strix R9285 DC2OC 2GD5

Kernel: amd-staging-drm-next 6e62bc7a123b "drm/amdgpu:Always save uvd vcpu_bo in VM Mode"

Bug report as discussed in bug 100919.
Possibly related to bug 91202.
Comment 1 Thomas R. 2018-03-10 23:33:42 UTC
Created attachment 137980 [details]
dmesg of boot, start of X and xrandr
Comment 2 Thomas R. 2018-05-17 07:39:30 UTC
Created attachment 139608 [details]
dmesg of boot, start of X, xrandr with current staging

Still persists in commit dbf4f8b16fde from Tuesday, see dmesg.
Comment 3 Thomas R. 2018-05-17 07:42:50 UTC
As you can see, I still get

[drm] dce_get_required_clocks_state: clocks unsupported disp_clk 681000 pix_clk 148500

Is there anything I can do to give you more information?
Comment 4 Michel Dänzer 2018-05-17 07:47:08 UTC
(In reply to Thomas R. from comment #3)
> [drm] dce_get_required_clocks_state: clocks unsupported disp_clk 681000
> pix_clk 148500

FWIW, I get the same message with Tonga, with a single DVI connection. I haven't noticed any obvious ill effects related to it though, so it might not be relevant for this issue.
Comment 5 Thomas R. 2018-05-21 17:59:45 UTC
Hm. Well the current state of this machine is: I got an old working AMD DC kernel (4.11) that is starting to give me trouble, and nothing current that works. I'd be willing to bisect from there to current, but there are other bugs and problems in between (some linked in first post) that make me not very hopeful :/.
Comment 6 Thomas R. 2018-09-05 17:20:20 UTC
Tested with 4.18.5, same behaviour.
Comment 7 Thomas R. 2018-10-22 17:26:21 UTC
I've got news! With 4.19, the first modeset will still disable the second monitor,  including when going into X (without mode change), but after changing the resolution to something else and back again, it now comes up reliably. This is much better than before. Also, I get this in dmesg

[drm] dce110_link_encoder_construct: Failed to get encoder_cap_info from VBIOS with error code 4!

on startup.

I don't know if this helps, and I'd be still willing to help debug given instructions.
Comment 8 Thomas R. 2018-10-22 22:36:38 UTC
Apart from bootup, coming back from suspend also has that one screen dead at first, and also fixable by changing resolution and back.
Comment 9 Thomas R. 2019-04-15 17:06:19 UTC
I'm unsure if I should file a new bug at this point, but here is an update for the LTS kernel:

4.19.20 breaks functionality again, now the second screen is reliably dead at 1080p (native resolution). I could bisect down to 0857b8439b6b9ce388e47652420ac083ea5f08d6 by Yogesh Mohan Marimuthu - drm/amd/display: calculate stream->phy_pix_clk before clock mapping.

It's the same for 4.20.17 and 5.0.6, I assume they contain the patch, too. I will attach debug kernel logs for both 4.19.20+ before the patch (working after screen reset as described above) and after.
Comment 10 Thomas R. 2019-04-15 17:59:44 UTC
Created attachment 143977 [details]
Kernel log with debug of 4.19.20+ before patch, including screen reset to get it to work
Comment 11 Thomas R. 2019-04-15 18:00:25 UTC
Created attachment 143978 [details]
Kernel log with debug of 4.19.20+ after patch, including screen reset that does nothing
Comment 12 Martin Peres 2019-11-20 07:47:55 UTC
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