Logs are present at https://pantheon.corp.google.com/storage/browser/chromiumos-test-logs/bugfiles/cros/755752/?debugUI=CLOUD

We see a pass result on kb_input test - https://wmatrix.googleplex.com/unfiltered?hide_missing=True&tests=platform_InputBrightness&releases=61&platforms=swanky&days_back=10
The test emulates keys pressed by setting event code for the kb input device.
This should be keyboard/kernel issue.

snanda@ this is currently a beta blocker. Will you please take a look and let us know who can take a look at this? This doesn't look like a beta blocker. WDYT?

Are the brightness keys broken on Swanky only or on other platforms too? Probably a beta blocker if it is indeed broken more widely.

Squawks in Chrome OS 9765.30.0, 61.0.3163.51 works fine. 

Can we try 9765.30.0, 61.0.3163.51 on swanky as well?

Also, to be clear on swanky are we trying the brightness up / down keys on the built-in keyboard or F6 / F7 on an external USB keyboard?

helenzhang@ can you please update results based on comment #7 by snanda@?

@comment #7
Still able to reproduce this issue on swanky 9765.30.0, 61.0.3163.51 

Facing same issue with built-in keyboard and USB keyboard.

Note: Only level 0 brightness(Display goes balck) is working.

This is display/drm related as I can see the backlight requests arriving in the driver when keys are pressed,

2017-08-18T10:08:05.791546-07:00 DEBUG kernel: [   43.479280] [drm:intel_backlight_device_update_status] updating intel_backlight, brightness=13085/65535
2017-08-18T10:08:05.791571-07:00 DEBUG kernel: [   43.479292] [drm:intel_panel_actually_set_backlight] set backlight PWM = 13085
2017-08-18T10:08:05.791576-07:00 DEBUG kernel: [   43.479308] [drm:edp_panel_vdd_on] Turning eDP port C VDD on
2017-08-18T10:08:05.791579-07:00 DEBUG kernel: [   43.479319] [drm:edp_panel_vdd_on] PP_STATUS: 0x80000008 PP_CONTROL: 0xabcd000f
2017-08-18T10:08:05.811078-07:00 DEBUG kernel: [   43.499964] [drm:intel_backlight_device_update_status] updating intel_backlight, brightness=12827/65535
2017-08-18T10:08:05.811102-07:00 DEBUG kernel: [   43.499972] [drm:intel_panel_actually_set_backlight] set backlight PWM = 12827

Sontis also mentioned that the screen stayed black after s2r.  The mosaic was still working but backlight no longer does.

We could potentially see regression from power_Idle measurement results (keyval level_backlight_max & level_backlight_current) but there's no coverage for R61

https://wmatrix.googleplex.com/unfiltered?suites=power_build&releases=61&platforms=swanky

couple of runs on 62,

https://wmatrix.googleplex.com/testrun/unfiltered?test_ids=537260333

But the logs aren't available, (500 internal error)

https://ubercautotest.corp.google.com/tko/retrieve_logs.cgi?job=/results/135801866-chromeos-test/chromeos4-row9-rack13-host9/power_Idle.AC_OFFLINE

-----------------
So back to logs (attached)

The one thing I see is recently added controls for backlight over aux,

./messages:2017-08-18T10:07:24.011226-07:00 DEBUG kernel: [    0.449721] [drm:intel_dp_aux_init_backlight_funcs] AUX Backlight Control Supported!

Now that should ONLY activate for panels edp panels supported 1.4 via,

https://chromium-review.googlesource.com/c/606779 # landed in 9765.22.0

And reading panel's DPCD[0] its = 12 -> 1.3 via,

# define DP_EDP_13			    0x02

But then we shouldn't see the debug message.

Adding i915.enable_dpcd_backlight=0 to the bootargs solves the problem.

Opal can you have a look?

Deleted: debug-logs_20170818-101050_swanky.tgz 137 KB

debug-logs_20170818-101050_swanky.tgz 137 KB Download

Panel dpcd is lying, it claim that PWM pin is not supported
so it didn't fallback to that even panel is eDP 1.3

At dpcd[0x702] == 0xf6 which mean bit0 == 0 and bit1 == 1

From the spec (see picture), this mean
1. Panel can't use PWM PIN to adjust brightness
2. Panel can use AUX to adjust brightness

But the reality is the opposite of what it claim using DPCD.

# cat /sys/kernel/debug/dri/0/eDP-1/i915_dpcd
0000: 12 0a c2 41 00 00 01 c0 02 00 00 00 1f 0b 00
0070: 01 00
0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0100: 0a 82 00 00 00 00 00 00 01 08 00
0200: 01 00 77 00 01 01 00 00
0600: 01
0700: 02
0701: b7 f6 00 00
0720: 01 1a 2a 5b 0a 04 0a 00 84 00 00 01 00 ff ff 03
0732: 00 14


Upload https://crrev.com/c/622047 + merge request

Deleted: 702.png 307 KB

	702.png 307 KB View Download

This bug requires manual review: M61 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), ketakid@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Approving merge to M61 Chrome OS.

This bug requires manual review: M61 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), ketakid@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Approving merge to M61 Chrome OS.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/kernel/+/b7e444d5698fa25b271471cba61e2dedf61a44e0

commit b7e444d5698fa25b271471cba61e2dedf61a44e0
Author: Puthikorn Voravootivat <puthik@chromium.org>
Date: Sat Aug 19 01:53:25 2017

CHROMIUM: Don't trust DPCD for panel earlier than eDP 1.4

Swanky panel has DPCD 702h = 0xf6 which means panel only support
AUX to adjust brightness not the PWM pin. But actually it is
opposite of what it is claiming in DPCD register.

This CL make driver to always use PWM pin to adjust brightness
for panel eariler than eDP 1.4 even when the panel DPCD said
that PWM pin is not supported.

BUG= chromium:755752 
TEST=Swanky brightness settings work again.

Change-Id: I305b72fc9c7f19581cc350bd3475a18cacef1da8
Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/622047
Reviewed-by: Todd Broch <tbroch@chromium.org>

[modify] https://crrev.com/b7e444d5698fa25b271471cba61e2dedf61a44e0/drivers/gpu/drm/i915/intel_dp_aux_backlight.c

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/kernel/+/117a2358b43e1084a47e8ecc2079cebebd951499

commit 117a2358b43e1084a47e8ecc2079cebebd951499
Author: Puthikorn Voravootivat <puthik@chromium.org>
Date: Sat Aug 19 02:11:56 2017

CHROMIUM: Don't trust DPCD for panel earlier than eDP 1.4

Swanky panel has DPCD 702h = 0xf6 which means panel only support
AUX to adjust brightness not the PWM pin. But actually it is
opposite of what it is claiming in DPCD register.

This CL make driver to always use PWM pin to adjust brightness
for panel eariler than eDP 1.4 even when the panel DPCD said
that PWM pin is not supported.

BUG= chromium:755752 
TEST=Swanky brightness settings work again.

Change-Id: I305b72fc9c7f19581cc350bd3475a18cacef1da8
Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/622047
Reviewed-by: Todd Broch <tbroch@chromium.org>
(cherry picked from commit b7e444d5698fa25b271471cba61e2dedf61a44e0)
Reviewed-on: https://chromium-review.googlesource.com/621276

[modify] https://crrev.com/117a2358b43e1084a47e8ecc2079cebebd951499/drivers/gpu/drm/i915/intel_dp_aux_backlight.c

Verified in Chrome OS 9765.38.0, 61.0.3163.61.

Issue 759939 has been merged into this issue.

Verified - this problem also occurs on my Toshiba CB 2 
Platform
9765.31.0 (Official Build) beta-channel swanky
Firmware
Google_Swanky.5216.238.5

This is fixed in R61-9765.33.0 / R62-9857.0.0

 Issue 758637  has been merged into this issue.