| Summary: | Broken backlight selected when apple gmux backlight driver present | ||||||
|---|---|---|---|---|---|---|---|
| Product: | xorg | Reporter: | Austin Lund <austin.lund> | ||||
| Component: | Driver/intel | Assignee: | Chris Wilson <chris> | ||||
| Status: | RESOLVED FIXED | QA Contact: | Xorg Project Team <xorg-team> | ||||
| Severity: | normal | ||||||
| Priority: | medium | ||||||
| Version: | unspecified | ||||||
| Hardware: | Other | ||||||
| OS: | Linux (All) | ||||||
| Whiteboard: | |||||||
| i915 platform: | i915 features: | ||||||
| Attachments: |
|
||||||
|
Description
Austin Lund
2012-07-24 02:11:48 UTC
Can you quickly test whether the native/platform/raw backlight detection of SNA works correctly? commit de707b7dc853a3b315ead9789d5ca541412c99bc Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Wed Jul 25 09:05:46 2012 +0100 uxa: Add Apple's gmux to the list of known preferred backlights Reported-by: Austin Lund <austin.lund@gmail.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=52423 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> In SNA accel method the backlight isn't working. I get: (II) intel(0): found backlight control interface acpi_video0 (type 'firmware') This is the present but non-functional backlight control Hmm, so much for believing the kernel to advertise a method to choose. This definitely contradicts the 'only one driver per device' rule... Can you please tell me what /sys/class/backlight/gmux_backlight/type describes itself as? $ cat /sys/class/backlight/gmux_backlight/type platform Just as a note, this buggyness with the backlights is known by the kernel devs. There were patches applied to unregister backlights which weren't working in BIOS compatibility mode. But in UEFI mode there is no way for the kernel to know that the acpi methods just don't do anything to the actual brightness of the backlight. It seems there is no way currently for the kernel to unreigster the acpi backlight when the gmux backlight driver finds the gmux hardware (as it is always the best choice if the gmuxer is present). A bit of greping confirms that only the ACPI are marked as firmware devices and we have preferred the known 'platform' devices in the past over those... commit 0ab6d7a50d37cf4454577cb8c333d4b8683aa054 Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Wed Jul 25 12:20:36 2012 +0100 sna: Prefer platform backlight devices over firmware This is in contrast to libbacklight but closer to our original code as we prefer a known custom backlight controller over the ACPI interfaces. As only the ACPI interfaces are marked as firmware, and the custom backlight controllers as platform, we therefore need to prefer platform backlight devices. Reported-by: Austin Lund <austin.lund@gmail.com> References: https://bugs.freedesktop.org/show_bug.cgi?id=52423 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Those commits make it all work for SNA accel. |
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.