Bug 16405

Summary: Brightness Adjustment on Toshiba nb305 Netbooks is non-functional.
Product: Drivers Reporter: Cody P Schafer (devel)
Component: Video(DRI - Intel)Assignee: drivers_video-dri-intel (drivers_video-dri-intel)
Status: CLOSED CODE_FIX    
Severity: normal CC: devel, dmaz, jbarnes, lenb, maciej.rutecki, mjg59-kernel, rjw
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.35-rc4-00131-ge467e10 Tree: Mainline
Regression: Yes
Bug Depends on:    
Bug Blocks: 16055    
Attachments: acpidump output
test patch which fixes the regression

Description Cody P Schafer 2010-07-15 23:40:53 UTC
Overview:
The fn-{brightness up, brightness down} keys on the Toshiba nb305 netbook do not adjust the brightness, nor do they generate ACPI events.

Steps to reproduce:
1.) Boot kernel on a nb305.
2.) Press fn-f5 or fn-f6.

Actual Results:
Brightness of LVDS display stays the same. No output from acpi_listen.

Expected Results:
Change in the brightness of the LVDS display. Video brightness event from acpi_listen.

Bisected: 
First bad commit: 74a365b3f354fafc537efa5867deb7a9fadbfe27
"ACPI: Populate DIDL before registering ACPI video device on Intel"
Comment 1 Matthew Garrett 2010-07-15 23:44:20 UTC
Ok. Could you please attach the output of the acpidump command?
Comment 2 Cody P Schafer 2010-07-15 23:49:28 UTC
Created attachment 27127 [details]
acpidump output

Attached acpidump.
Comment 3 Rafael J. Wysocki 2010-07-22 21:36:01 UTC
First-Bad-Commit : 74a365b3f354fafc537efa5867deb7a9fadbfe27
Handled-By : Matthew Garrett <mjg59-kernel@srcf.ucam.org>
Comment 4 Cody P Schafer 2010-07-24 05:59:22 UTC
I enabled drm driver debug (cmdline += drm.debug=0x02) and noted that
the "Public ACPI methods not supported" message was encountered.

By calling acpi_video_register even on error, the brightness keys function again.
Comment 5 Cody P Schafer 2010-07-24 06:00:39 UTC
Created attachment 27236 [details]
test patch which fixes the regression
Comment 6 Rafael J. Wysocki 2010-07-24 22:49:13 UTC
Patch : https://bugzilla.kernel.org/attachment.cgi?id=27236
Comment 7 Rafael J. Wysocki 2010-09-12 19:00:44 UTC
Fixed by commit 54b9b308fa39e5147e2edde3492d8650b957be6c .