Date: Fri, 3 Feb 2023 08:40:17 +0100 From: Emmanuel Vadot <manu@bidouilliste.com> To: "Poul-Henning Kamp" <phk@phk.freebsd.dk> Cc: "parv/FreeBSD" <parv.0zero9+freebsd@gmail.com>, freebsd-current@freebsd.org Subject: Re: Could not change brightness anymore with i915kms & acpi_video modules c 202211 Message-ID: <20230203084017.b1e8dc1f9116d8a55a1c2cfd@bidouilliste.com> In-Reply-To: <202302022058.312Kwwj8003814@critter.freebsd.dk> References: <CABObuOoUDHrUF6FyTwEXTrnt3ztkoAR4x5vzjcNp7H-4F4XE7A@mail.gmail.com> <CABObuOoik3j_fsM=LciqRC8QrjJAs4o-hBYU_ZDE9wx=WJBBVw@mail.gmail.com> <202302022058.312Kwwj8003814@critter.freebsd.dk>
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On Thu, 02 Feb 2023 20:58:58 +0000 "Poul-Henning Kamp" <phk@phk.freebsd.dk> wrote: > -------- > parv/FreeBSD writes: > > > > Does backlight(8) works for you? > > > > Thanks for the clue. It does! It does ... > > > > - I get the same number back via "backlight" without any arguments as > > what I gave it earlier. There was no reporting of value being > > subtracted by one; > > Sorry for the delay in reporting back. > > I consistently read one less back, except for 0 and 100. Even 50 ? > (This could easily be a BIOS bug) At first I though so too but I'll need to check if this isn't a rounding error between backlight(4) and linuxkpi wrappers. I know that some hardware don't have a perfect pwm controller for the backlight and so you have only some steps that it can do (but you don't know them). > It also looks like the "no-op" behaviour I reported previously have > gone away with my latest kernel update. Weird, nothing has changed for a while in this area but happy that it's fixed ;) > But I see a new behaviour, but this may be intentional: When it > comes out of screen-blanking, it goes to 100 (and reports 100). I'm not too surprised about this behavior, there is probably something that we could do about it but this will need more digging in linux framework and the drm drivers. > Also happens when an external monitor is connected, which is a > bit annoying... So if you have, let's say brightness at 50%, and you plug an external monitor, brightness goes up to 100% ? > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > -- Emmanuel Vadot <manu@bidouilliste.com> <manu@freebsd.org>
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