[Bug 200667] New: [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[Bug 200667] New: [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

            Bug ID: 200667
           Summary: [AMDGPU] stacktrace in dmesg, starting at
                    drm_dp_i2c_do_msg
           Product: Drivers
           Version: 2.5
    Kernel Version: 4.17.10
          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: CWidmer@umbrox.de
        Regression: No

Created attachment 277569
  --> https://bugzilla.kernel.org/attachment.cgi?id=277569&action=edit
Full dmesg output from kernel 4.18-r6

When I changed my kernel from 4.17.9 to 4.17.10 (both patched with the Gentoo
patchset), a stacktrace started to appear in the kernel messages. To check
whether this is still an issue in mainline and not related to the distribution
kernel, I tried 4.18-r6 which also shows the issue.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 200667] [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

--- Comment #1 from Christian Widmer (CWidmer@umbrox.de) ---
Created attachment 277571
  --> https://bugzilla.kernel.org/attachment.cgi?id=277571&action=edit
Kernel configuration

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 200667] [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

--- Comment #2 from Christian Widmer (CWidmer@umbrox.de) ---
Created attachment 277573
  --> https://bugzilla.kernel.org/attachment.cgi?id=277573&action=edit
lspci

I am using an RX 580.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 200667] [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

--- Comment #3 from Christian Widmer (CWidmer@umbrox.de) ---
I might add simply booting the kernel is all that is needed to trigger the
issue. The stacktraces automatically appear during the boot process.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 200667] [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

Alex Deucher (alexdeucher@gmail.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |alexdeucher@gmail.com

--- Comment #4 from Alex Deucher (alexdeucher@gmail.com) ---
Can you bisect?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 200667] [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

--- Comment #5 from Christian Widmer (CWidmer@umbrox.de) ---
The bisect identified commit 9168c089a2122606e2c01f6fbeda85ff950ac189 (Revert
"drm/amd/display: Don't return ddc result and read_bytes in same return value",
upstream commit 5292221d6ddfed75e5b46cd42237a677094b99f3). And a quick test
with reverting this change in my distribution's 4.17.10 kernel and in the
mainline 4.18-rc6 kernel indeed made the stacktrace disappear.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 200667] [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

--- Comment #6 from Alex Deucher (alexdeucher@gmail.com) ---
The warning is harmless.  As per the commit message, this is fixed properly for
4.19 with the following patches:

    This breaks DDC in certain cases.  Revert for 4.18 and previous kernels.
    For 4.19, this is fixed with the following more extensive patches:
    drm/amd/display: Serialize is_dp_sink_present
    drm/amd/display: Break out function to simply read aux reply
    drm/amd/display: Return aux replies directly to DRM
    drm/amd/display: Right shift AUX reply value sooner than later
    drm/amd/display: Read AUX channel even if only status byte is returned

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 200667] [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

--- Comment #7 from Christian Widmer (CWidmer@umbrox.de) ---
For the sake of completeness I have just tested linux-next which contains all
those patches and the warning is indeed gone. Thank you for your responses!

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 200667] [AMDGPU] stacktrace in dmesg, starting at drm_dp_i2c_do_msg

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=200667

--- Comment #8 from Christian Widmer (CWidmer@umbrox.de) ---
As expected, the warning is indeed gone with the recently released stable
kernel 4.19.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel