[Bug 96571] [CHV] Backlight init fails on Surface 3 if module load order is wrong

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=96571

--- Comment #10 from viric at viric.name ---
I guess that the pwm driver patches are OK, as they were in this my LPSS:

http://www.spinics.net/lists/intel-gfx/msg92110.html

But the problem is that there is no glue between any PWM and i915 other than
drivers/video/backlight/pwm_bl.c. It only adds support for *some* PWM devices
to be used as backlight, and only in CONFIG_OF (embedded x86, with devicetree,
non-ACPI).

So, PWM works, i915 works, but the pwm-backlight glue called by i915 is not
present in x86 ACPI.

http://lxr.free-electrons.com/source/drivers/video/backlight/pwm_bl.c#L195

See how pwm_backlight_probe() calls just pwm_backlight_parse_dt(), that for
non-CONFIG_OF just returns -ENODEV. Then, i915 never finds a backlight pwm for
an ACPI (non-CONFIG_OF) system).

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are on the CC list for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20160711/a1b87a38/attachment.html>