Bug 251844

Summary:	Controlling screen brightness (i2c, ddc, ...)
Product:	Base System	Reporter:	Hannes Hauswedell <h2+fbsdports>
Component:	misc	Assignee:	freebsd-bugs (Nobody) <bugs>
Status:	Closed Not A Bug
Severity:	Affects Some People
Priority:	---
Version:	Unspecified
Hardware:	Any
OS:	Any

Description Hannes Hauswedell 2020-12-14 19:28:29 UTC

Linux folks have support for regulating screen brightness via software:
https://github.com/rockowitz/ddcutil

But it doesn't seem like this works on FreeBSD -- although in theory we have the required subsystems, or not?

The author of the tool has is willing to add FreeBSD support:
https://github.com/rockowitz/ddcutil/issues/118
but needs a little help from FreeBSD hackers. Could someone provide him with the required information?

Thank you very much!

Comment 1 Andriy Gapon freebsd_committer

2020-12-14 22:48:53 UTC

Please use one or more of forums suggested here https://www.freebsd.org/community.html to discuss and promote your proposal.

Comment 2 Conrad Meyer freebsd_committer

2020-12-15 02:28:53 UTC

DDC I2C support depends on GPU drivers providing an ioctl interface.  The FreeBSD nvidia driver *does not* provide the ioctls, but the Linux nvidia driver does (support is present in the binary blob, but not exposed to userspace).  I'm not sure if we have DDC/I2C ioctl support in either the Intel or AMD GPU drivers.

Comment 3 Andriy Gapon freebsd_committer

2020-12-15 11:36:35 UTC

When drm drivers were in base they used to expose standard /dev/iic devices.
It no longer seems to be the case with the linuxkpi based drivers.

Comment 4 Hannes Hauswedell 2020-12-15 14:18:25 UTC

(In reply to Conrad Meyer from comment #2)

Thank you for responding to this! Such a change to the NVIDIA-driver would be very much appreciated! Would be very willing to help test this!

(In reply to Andriy Gapon from comment #3)
OK, seeing as these things were provided by drivers before and are not any more, is it not correct to assume that this is a FreeBSD issue and thus the STATUS of this problem report should be re-opened?

Comment 5 Andriy Gapon freebsd_committer

2020-12-16 08:37:49 UTC

(In reply to Hannes Hauswedell from comment #4)
It's something that FreeBSD is missing , yes, but I doubt that a problem / bug report is appropriate here.

Think of "FreeBSD does not run on Apple silicon".
It's true and it may be a problem for someone.
But it is not a bug per se.
And opening a report for it would do very little to get the actual work done.

Same here.