Bug 56011 - Backlight controls not working properly on Lenovo Thinkpad Edge e14 (0578A21)
Summary: Backlight controls not working properly on Lenovo Thinkpad Edge e14 (0578A21)
Status: CLOSED DUPLICATE of bug 42861
Alias: None
Product: ACPI
Classification: Unclassified
Component: Power-Video (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Aaron Lu
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-03-31 10:33 UTC by Artem Savkov
Modified: 2013-04-08 23:51 UTC (History)
4 users (show)

See Also:
Kernel Version: 3.9.0-rc4-next-20130328
Subsystem:
Regression: No
Bisected commit-id:


Attachments
dmidecode output (12.35 KB, text/plain)
2013-03-31 10:34 UTC, Artem Savkov
Details
acpidump output (254.44 KB, text/plain)
2013-03-31 10:34 UTC, Artem Savkov
Details
disassembled DSDT (416.81 KB, text/x-dsl)
2013-03-31 10:35 UTC, Artem Savkov
Details
Enhance _BQC quirk check (2.13 KB, patch)
2013-03-31 12:33 UTC, Aaron Lu
Details | Diff

Description Artem Savkov 2013-03-31 10:33:59 UTC
_BQC seems to always return zero making backlight control to not work properly, i.e. only 2 lower brightness levels are available.

Problem showed up after a bunch of fixes in acpi/video.c:
994fa63c5b126df6e9f31ef4e09000e2e243234b "ACPI / video: Fix applying indexed initial brightness value."
2d4128a25206685aaccaf14220c8436b11c6dc01 "ACPI / video: Make logic a little easier to understand."
a89803df9c9b2d023227c48503066a728f1fed36 "ACPI / video: Fix brightness control initialization for some laptops."

With this commits reverted controls works fine but only because BQC get's disabled due to invalid value being returned on initial BQC call.
Comment 1 Artem Savkov 2013-03-31 10:34:17 UTC
Created attachment 96721 [details]
dmidecode output
Comment 2 Artem Savkov 2013-03-31 10:34:42 UTC
Created attachment 96731 [details]
acpidump output
Comment 3 Artem Savkov 2013-03-31 10:35:26 UTC
Created attachment 96741 [details]
disassembled DSDT
Comment 4 Aaron Lu 2013-03-31 12:33:30 UTC
Created attachment 96751 [details]
Enhance _BQC quirk check

Hi Artem,

Please test if this patch fixed the problem, thanks. Apply on top of the -next tree.
Comment 5 Artem Savkov 2013-03-31 13:01:55 UTC
Hi Aaron,

Yes, this patch works for me. BQC is disabled on init as intended.
Comment 6 Aaron Lu 2013-04-01 05:14:56 UTC
(In reply to comment #5)
> Hi Aaron,
> 
> Yes, this patch works for me. BQC is disabled on init as intended.

And does it work as expected afterwards?
Comment 7 Artem Savkov 2013-04-01 05:32:56 UTC
Yes it just uses backlight->curr so things are back to normal, i.e. both buttons and xbacklight work normally.
Comment 8 Aaron Lu 2013-04-03 03:16:35 UTC
Hi Artem,

I'll mark this bug as a duplicate of #42861, though they are not exactly the same, but they share something in common and can be solve in the same way.

And I just proposed an updated patch, it shouldn't affect you, but if you have time, please kindly give it a test, thanks.

*** This bug has been marked as a duplicate of bug 42861 ***

Note You need to log in before you can comment on or make changes to this bug.