[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 2002 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

            Bug ID: 106228
           Summary: amdgpu reads back brightness 0 (which is not true) if
                    checked before a brightness has been explicitly set
           Product: DRI
           Version: unspecified
          Hardware: Other
                OS: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/AMDgpu
          Assignee: dri-devel@lists.freedesktop.org
          Reporter: jian-hong@endlessm.com

Created attachment 139091
  --> https://bugs.freedesktop.org/attachment.cgi?id=139091&action=edit
The full dmesg

I have tried to install Linux OS on ASUS laptop which is equipped with AMD
Ryzen 5 2500U with Radeon Vega Mobile Gfx.

When the Linux installation completed and entered to the OS, the brightness of
display looks normal but the brightness bar is shown as the lowest level within
the display's brightness GUI setting.

Also check "cat /sys/class/backlight/amdgpu_bl0/brightness" and it is 0.

After a system reboot, Brightness is dimmed to the lowest level.
Check "cat /sys/class/backlight/amdgpu_bl0/brightness" again and it is 12.

To make sure it is the problem that "system always reads back brightness 0 if
checked before a brightness has been explicitly set".
I disable all of the brightness setting applications, including masking
systemd-backlight service and than reboot.
"cat /sys/class/backlight/amdgpu_bl0/brightness" before set brightness manually
again and it reads back 0, but the brightness of display looks normal actually.
Then, if I drag the brightness bar in GUI, the actual brightness changes and
the "/sys/class/backlight/amdgpu_bl0/brightness" goes to the right value.
And, I reboot again, then the same things happen again.

I also tried this with kernel v4.17.0-rc2.  It still has the same problem.

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 3504 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 391 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

--- Comment #1 from Alex Deucher <alexdeucher@gmail.com> ---
Harry, I thought we fixed something like this recently.  Maybe this patch?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c3d7bad88e3b35b981eecc1645ddbb3f13a8b54f

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 1421 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 471 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

--- Comment #2 from Harry Wentland <harry.wentland@amd.com> ---
That patch only affects Carrizo and should only be needed for S3.

We don't see this issue with Ubuntu 18.04 on a Raven laptop we have available.
The OS (Gnome) shows brightness as expected on boot.

I wonder if some laptops behave differently but I can't think why.

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 1371 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 296 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

--- Comment #3 from Daniel Drake <dan@reactivated.net> ---
Do you have any specific debugging suggestions?
Can we ship an affected laptop to you for diagnosis?

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 1191 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 395 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

--- Comment #4 from David Francis <david.francis@amd.com> ---
Created attachment 140795
  --> https://bugs.freedesktop.org/attachment.cgi?id=140795&action=edit
Patch that should fix the problem

Could you try out this patch and check if it works?  Thanks.

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 1537 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 346 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

--- Comment #5 from Daniel Drake <dan@reactivated.net> ---
Created attachment 140809
  --> https://bugs.freedesktop.org/attachment.cgi?id=140809&action=edit
additional patch

this patch may also be required

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 1451 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 755 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

--- Comment #6 from jian-hong@endlessm.com ---
Apply "[PATCH] drm/amdgpu: Read back max backlight value at boot" to Linux
4.18.0-rc6 kernel.

I disable all of the brightness setting applications, including masking
systemd-backlight service and than reboot.
"cat /sys/class/backlight/amdgpu_bl0/brightness" before set brightness manually
again and it reads back 255 (the maximum brightness).

If I unmask systemd-backlight service and than reboot for test, "cat
/sys/class/backlight/amdgpu_bl0/brightness" before set brightness manually
again and it reads back the brightness which is saved before last reboot.

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 1666 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 403 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

--- Comment #7 from jian-hong@endlessm.com ---
Applied both "[PATCH] drm/amdgpu: Read back max backlight value at boot" and
"[PATCH] drm/amd/display: Implement backlight_ops.get_brightness" to Linux
4.18.0-rc6 kernel.

I got the same behavior as previous comment.

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 1304 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 356 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

--- Comment #8 from David Francis <david.francis@amd.com> ---
When systemd-backlight is disabled, on reboot is the actual brightness coming
from the monitor maximum?  

If it is, I believe this is working as intended.

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 1254 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 106228] amdgpu reads back brightness 0 (which is not true) if checked before a brightness has been explicitly set

[bugzilla-daemon]

[-- Attachment #1.1: Type: text/plain, Size: 501 bytes --]

https://bugs.freedesktop.org/show_bug.cgi?id=106228

jian-hong@endlessm.com changed:

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

--- Comment #9 from jian-hong@endlessm.com ---
Hi David,

Yes!  It is. Thanks

-- 
You are receiving this mail because:
You are the assignee for the bug.

[-- Attachment #1.2: Type: text/html, Size: 2141 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel