linux-kernel - Re: linux-next 20160512 - ACPI issue with screen brightness

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <29833.1463789712@turing-police.cc.vt.edu>
Date:	Fri, 20 May 2016 20:15:12 -0400
From:	Valdis.Kletnieks@...edu
To:	Aaron Lu <aaron.lu@...el.com>
cc:	"Rafael J. Wysocki" <rafael@...nel.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Len Brown <lenb@...nel.org>
Subject: Re: linux-next 20160512 - ACPI issue with screen brightness

On Fri, 20 May 2016 15:17:20 +0800, Aaron Lu said:
> On Fri, May 20, 2016 at 03:02:08AM -0400, Valdis.Kletnieks@...edu wrote:
> > With the patches reverted:
> > 
> > [/sys/class/backlight/acpi_video0] grep . *bright*
> > actual_brightness:95
> > brightness:95
> > max_brightness:95
> > 
> > And the weird part inside the kernel - on a kernel that has the problem,
> > /sys/class/backlight is *empty* - only '.' and '..' entries.
> > 
> > No, I don't understand why the acpi_video0 entry isn't created when that
> > commit is in place.
>
> The commit probably makes acpi_video_init_brightness bail out for some
> reason, adding debug prints under those "if (result)" in
> acpi_video_init_brightness should help to identify where it goes wrong.
>
> And your acpidump please, thanks.

The dmesg output:

[    1.966400] ACPI: Power Button [PWRF]
[    1.969759] ACPI: Video Device [VID] (multi-head: yes  rom: yes  post: no)
[    1.969829] acpi_evaluate_BCL failed, 4097
[    1.969866] acpi_evaluate_BCL failed, 4097
[    1.969898] acpi_evaluate_BCL failed, 4097
[    1.969930] acpi_evaluate_BCL failed, 4097
[    1.969961] acpi_evaluate_BCL failed, 4097
[    1.969994] acpi_evaluate_BCL failed, 4097
[    1.970045] acpi_evaluate_BCL failed, 4097
[    1.970077] acpi_evaluate_BCL failed, 4097
[    1.970621] acpi_evaluate_BCL failed, 5
[    1.970652] Could not query available LCD brightness level
[    1.970692] acpi_video_get_levels failed, -19
[    1.973516] ACPI Error: Current brightness invalid (20160422/video-368)
[    1.973528] acpi_video_bqc_quirk failed, -22
[    1.973567] acpi_evaluate_BCL failed, 5
[    1.973597] Could not query available LCD brightness level
[    1.973636] acpi_video_get_levels failed, -19
[    1.973672] acpi_evaluate_BCL failed, 5
[    1.973701] Could not query available LCD brightness level
[    1.973741] acpi_video_get_levels failed, -19
[    1.973777] acpi_evaluate_BCL failed, 5
[    1.973807] Could not query available LCD brightness level
[    1.973847] acpi_video_get_levels failed, -19
[    1.973882] acpi_evaluate_BCL failed, 5
[    1.973911] Could not query available LCD brightness level
[    1.973951] acpi_video_get_levels failed, -19
[    1.973986] acpi_evaluate_BCL failed, 5
[    1.974439] Could not query available LCD brightness level
[    1.974479] acpi_video_get_levels failed, -19
[    1.974529] acpi_evaluate_BCL failed, 5
[    1.974565] Could not query available LCD brightness level
[    1.974603] acpi_video_get_levels failed, -19
[    1.977783] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:14/LNXVIDEO:00/input/input4
[    1.980879] thermal LNXTHERM:00: registered as thermal_zone0
[    1.980884] ACPI: Thermal Zone [THM] (64 C)

acpidump is attached...

View attachment "acpidump.e6530.a17" of type "text/plain " (279015 bytes)