https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #1 from Duncan Roe duncan_roe@optusnet.com.au --- Hardware is as in Bug 108139

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #3 from Duncan Roe duncan_roe@optusnet.com.au --- The second bisect identifies 5099114ba3b2e5ae9fb487aeb3ae0434fe38a7da as the oldest commit showing the problem, which does not show in adjacent commit b646c1dc835b6b73884a88643c2534f1a4a1928f. In order to see either of these commits in git list, one first needs to git checkout 2bfb0b678e48dee76543bfa2079b7e42609332fb. (In reply to Duncan Roe from comment #0)

Created attachment 142239 [details] Git diff specifying 2 commits (GD is aliased to git diff)

(High severity because laptop is useless when travelling) With HDMI unplugged, X laptop screen is black with only a cursor. Cursor changes shape as it moves over xterm windows put there by xinitrc. Bisecting in git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git finds 2bfb0b678e48dee76543bfa2079b7e42609332fb has the problem but adjacent commit 9c24c10a2c1e1bb478b6bb70612d9e885aee044f does not. There is an oddity with git diff between these two: git diff <commit1> <commit2> produces copious output and a git warning (see attachment), but git checkout <commit2>; git diff <commit1> only shows one patched file (next attachment). You might want to try this - I re-cloned the repo in case the old one was corrupted but it made no difference.

Please ignore the git diff stuff above. After checking out 2bfb0b678e48dee76543bfa2079b7e42609332fb, I diffed the second commit in git list not realising that this was no longer 9c24c10a2c1e1bb478b6bb70612d9e885aee044f. The new bisect is the valid one

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #4 from Duncan Roe duncan_roe@optusnet.com.au --- After stripping the timestamps from good and bad copies of Xorg.0.log, the only significant difference between them appears to be gart size. See attachment 2

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #6 from Duncan Roe duncan_roe@optusnet.com.au --- (In reply to Duncan Roe from comment #4)

After stripping the timestamps from good and bad copies of Xorg.0.log, the only significant difference between them appears to be gart size. See attachment 2 [details] [review]

Sorry that is now attachment 1 after obsoleting the old one

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #8 from Duncan Roe duncan_roe@optusnet.com.au --- (In reply to Duncan Roe from comment #7)

(In reply to Duncan Roe from comment #6)

...

(In reply to Duncan Roe from comment #4)

...

After stripping the timestamps from good and bad copies of Xorg.0.log, the only significant difference between them appears to be gart size. See attachment 2 [details] [review] [review] [review]

Sorry that is now attachment 1 [details] [review] [review] after obsoleting the old one

In any case, don't follow the auto-generated attachment hyperlink. Just open the attachment

Ah ther you go - attachment numbers are global. See attachment 142250

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #10 from Duncan Roe duncan_roe@optusnet.com.au --- DRM_AMD_DC_FBC is not in my .config and never has been (from the RCS tree)

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #12 from Duncan Roe duncan_roe@optusnet.com.au --- Created attachment 142286 --> https://bugs.freedesktop.org/attachment.cgi?id=142286&action=edit Help for CONFIG_DRM_AMD_DC_FBC

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #14 from Duncan Roe duncan_roe@optusnet.com.au --- Commit 5099114ba3b2e5ae9fb487aeb3ae0434fe38a7da was authored by alexander.deucher@amd.com but Bugzilla says "CC: alexander.deucher@amd.com did not match anything" when I try to add his email

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #16 from Duncan Roe duncan_roe@optusnet.com.au --- Created attachment 142292 --> https://bugs.freedesktop.org/attachment.cgi?id=142292&action=edit O/P from dmesg

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #18 from Duncan Roe duncan_roe@optusnet.com.au --- Created attachment 142334 --> https://bugs.freedesktop.org/attachment.cgi?id=142334&action=edit Patch for Linux-19.0 to revert 5099114 & reinstate DRM_AMD_DC_FBC kconfig option

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #20 from Alex Deucher alexdeucher@gmail.com --- Created attachment 142348 --> https://bugs.freedesktop.org/attachment.cgi?id=142348&action=edit possible fix 2/2

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #22 from Duncan Roe duncan_roe@optusnet.com.au --- Created attachment 142350 --> https://bugs.freedesktop.org/attachment.cgi?id=142350&action=edit possible fix 1/2 updated for Linux 19.0

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #24 from Alex Deucher alexdeucher@gmail.com --- Does just removing this line from the code: value |= 0x84; also fix the issue?

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #26 from Duncan Roe duncan_roe@optusnet.com.au --- Created attachment 142382 --> https://bugs.freedesktop.org/attachment.cgi?id=142382&action=edit One-line patch as Alex requested

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #28 from Duncan Roe duncan_roe@optusnet.com.au --- Created attachment 142384 --> https://bugs.freedesktop.org/attachment.cgi?id=142384&action=edit Log of applying FBC patchset

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #30 from Alex Deucher alexdeucher@gmail.com --- Can you try this patch set? https://patchwork.freedesktop.org/series/52117/

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #32 from Duncan Roe duncan_roe@optusnet.com.au --- X displays normally with this patch set (as amended) applied to Linux 4.19.1 commit 07a03b97b9ce2a6430344386eeab9b16283b893f on branch linux-4.19.y of the stable tree. There was an oddity the first time I tried it which I have not been able to reproduce since: the X screen went dark after timing out (as normal) but it wouldn't light up again for keyboard presses, mouse clicks etc. I ahve tried numerous time to reproduce this but not managed, so I have to say the patch is good.

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #34 from Duncan Roe duncan_roe@optusnet.com.au --- (In reply to Alex Deucher from comment #33)

Does this patch fix the issue with fbc enabled? https://patchwork.freedesktop.org/patch/264806/

No. I get the black screen after entering *startx* (system boots to command-line prompt). However, I let the screen time out for a long time while I went checking for stuff. When I went to Ctrl-Alt-F1 to get back to command mode, a proper X display appeared. I rebooted (Had to power off owing to Bug 108464). This time I tried touching keys as soon as I noticed X had timed out but nothing would wake it up (like the "oddity" mentioned in Comment 32). Trying again, last time for tonight. Have taken the precaution of starting an xterm using my desktop's DISPLAY before starting X. Am following /var/log/debug (set up to log everything).

Nov 30 22:09:46 smallstar kernel: [ 697.279929] [drm:dc_commit_state [amdgpu]] dc_commit_state: 0 streams Nov 30 22:09:46 smallstar kernel: [ 697.280185] [drm:hwss_edp_backlight_control [amdgpu]] hwss_edp_backlight_control: backlight action: Off Nov 30 22:09:46 smallstar kernel: [ 697.312816] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 5ms in dce110_stream_encoder_dp_blank line:922 Nov 30 22:09:46 smallstar kernel: [ 697.313269] [drm:hwss_edp_power_control [amdgpu]] hwss_edp_power_control: Panel Power action: Off Nov 30 22:09:46 smallstar kernel: [ 697.329572] [drm:drm_mode_setcrtc [drm]] [CRTC:40:crtc-0] Nov 30 22:09:46 smallstar kernel: [ 697.329617] [drm:drm_mode_setcrtc [drm]] [CRTC:42:crtc-1] Nov 30 22:09:46 smallstar kernel: [ 697.329667] [drm:drm_mode_setcrtc [drm]] [CRTC:40:crtc-0]

Touch the Ctrl key at 22:15:08 (I was called away) and X display shows:

Nov 30 22:15:08 smallstar kernel: [ 1019.371568] [drm:drm_mode_setcrtc [drm]] [CRTC:40:crtc-0] Nov 30 22:15:08 smallstar kernel: [ 1019.371601] [drm:drm_mode_setcrtc [drm]] [CONNECTOR:44:eDP-1] Nov 30 22:15:08 smallstar kernel: [ 1019.378652] [drm:dc_commit_state [amdgpu]] dc_commit_state: 1 streams Nov 30 22:15:08 smallstar kernel: [ 1019.378727] [drm:dc_stream_log [amdgpu]] core_stream 0x00000000f8a1cb08: src: 0, 0, 1366, 768; dst: 0, 0, 1366, 768, colorSpace:1 Nov 30 22:15:08 smallstar kernel: [ 1019.378797] [drm:dc_stream_log [amdgpu]] ^Ipix_clk_khz: 76300, h_total: 1558, v_total: 816, pixelencoder:1, displaycolorDepth:1 Nov 30 22:15:08 smallstar kernel: [ 1019.378867] [drm:dc_stream_log [amdgpu]] ^Isink name: , serial: 0 Nov 30 22:15:08 smallstar kernel: [ 1019.378938] [drm:dc_commit_state [amdgpu]] ^Ilink: 0 Nov 30 22:15:08 smallstar kernel: [ 1019.379244] [drm:dce110_compressor_disable_fbc [amdgpu]] FBC status changed to 0 Nov 30 22:15:08 smallstar kernel: [ 1019.379501] [drm:hwss_edp_power_control [amdgpu]] hwss_edp_power_control: Panel Power action: On Nov 30 22:15:08 smallstar kernel: [ 1019.500815] [drm:enable_link_dp [amdgpu]] Link: 0 eDP panel mode supported: 1 eDP panel mode enabled: 1 Nov 30 22:15:08 smallstar kernel: [ 1019.503669] [drm:dc_link_dp_perform_link_training [amdgpu]] HBRx1 pass VS=0, PE=0 Nov 30 22:15:08 smallstar kernel: [ 1019.504331] [drm:hwss_edp_backlight_control [amdgpu]] hwss_edp_backlight_control: backlight action: On Nov 30 22:15:08 smallstar kernel: [ 1019.516877] [drm:dc_commit_state [amdgpu]] {1366x768, 1558x816@76300Khz}

https://bugs.freedesktop.org/show_bug.cgi?id=108577

--- Comment #40 from Duncan Roe duncan_roe@optusnet.com.au --- Created attachment 143006 --> https://bugs.freedesktop.org/attachment.cgi?id=143006&action=edit Diagnostic patches to determine which pointer is null

These patches are against Linux 4.19.12, commit 2a7cb228d29c3882c1414c10a44c5f3f59bfa44d in git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

https://bugs.freedesktop.org/show_bug.cgi?id=108577

Duncan Roe duncan_roe@optusnet.com.au changed:

What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |FIXED Status|NEW |RESOLVED

--- Comment #42 from Duncan Roe duncan_roe@optusnet.com.au --- Since Linux 5.1, I do not see this bug any more. So I guess it is "fixed".