Bug 48941
| Summary: | Error creating '/sys/class/backlight/radeon_bl' in radeon_atom_backlight_init() | ||
|---|---|---|---|
| Product: | Drivers | Reporter: | Igor Murzov (e-mail) |
| Component: | Video(DRI - non Intel) | Assignee: | drivers_video-dri |
| Status: | RESOLVED CODE_FIX | ||
| Severity: | normal | CC: | alexdeucher, florian |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 3.7.0-rc1 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: |
dmesg
lspci -vvv give each radeon_bl a unique name |
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Created attachment 83701 [details]
lspci -vvv
You have a hybrid laptop with with a mux to switch between the two GPUs. I suppose ideally we'd only create one bl device and switch control of it when the mux is switched. I'm not sure of the best way to do that off hand at the moment. Can I help somehow with this and other issue with hybrid systems with a mux? Looks like not much people have such configuration and linux becomes more and more buggy with regard to gpus on my laptop. I can help testing patches or may be bisect some regression for you or even inspect some code :] The acpi backlight control should still work. Created attachment 83751 [details]
give each radeon_bl a unique name
This patch should fix the issue, however, you'll have to use the appropriate bl device depending on which gpu is active.
The patch fixed the issue. I have two bl devices now: # tree /sys/class/backlight/ /sys/class/backlight/ ├── radeon_bl0 -> ../../devices/pci0000:00/0000:00:01.0/0000:01:05.0/drm/card0/card0-LVDS-1/radeon_bl0 └── radeon_bl1 -> ../../devices/pci0000:00/0000:00:02.0/0000:02:00.0/drm/card1/card1-LVDS-2/radeon_bl1 A patch referencing this bug report has been merged in Linux v3.7-rc3: commit 614499b4d844dcceae5ae2f1e53a2963789a8933 Author: Alex Deucher <alexander.deucher@amd.com> Date: Wed Oct 17 17:20:24 2012 -0400 drm/radeon: give each backlight a unique id Fixed. |
Created attachment 83691 [details] dmesg There is an error in my dmesg: sysfs: cannot create duplicate filename '/class/backlight/radeon_bl' and there is no '/sys/class/backlight/radeon_bl' after system boot.