From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Hogan Subject: Re: [REGRESSION] [v2] ACPI / video: Default lcd_only to true on Win8 ready and newer machines Date: Mon, 16 Apr 2018 14:02:12 +0100 Message-ID: <20180416130211.GA484@jamesdev> References: <20171223184147.12016-1-hdegoede@redhat.com> <20180414230746.GA29537@saruman> <20180415225403.GA6373@jamesdev> <18c72a70-577f-358e-fb82-095b75157a29@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="BOKacYhQ+x31HxR3" Return-path: Content-Disposition: inline In-Reply-To: <18c72a70-577f-358e-fb82-095b75157a29@redhat.com> Sender: stable-owner@vger.kernel.org To: Hans de Goede Cc: Zhang Rui , "Rafael J . Wysocki" , Len Brown , linux-acpi@vger.kernel.org, stable@vger.kernel.org, Sasha Levin , Greg Kroah-Hartman List-Id: linux-acpi@vger.kernel.org --BOKacYhQ+x31HxR3 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 16, 2018 at 01:07:50PM +0200, Hans de Goede wrote: > On 16-04-18 00:54, James Hogan wrote: > > On Sun, Apr 15, 2018 at 02:04:26PM +0200, Hans de Goede wrote: > > > When you say quirk do you mean you add something to > > > the kernel commandline to work around this? > >=20 > > No, it was automatic, in the source. I don't know this code well enough > > to know how they got it working. >=20 > Weird, if my only_lcd changes impact you then acpi_osi_is_win8() > returns true for you It rings a bell that this laptop claims win8 support. > you should get the intel backlight interface > by default, but maybe the i915 driver somehow detects that that > is not appropriate on your device ... ? >=20 > Before I can start working on a quirk to fix this I've some > questions: >=20 > 1) With recent kernels without the 965736ee654d commit, what is > the output of "ls /sys/class/backlight" ? $ ls -l /sys/class/backlight total 0 lrwxrwxrwx 1 root root 0 Apr 16 13:57 acpi_video0 -> ../../devices/pci0000:= 00/0000:00:02.0/backlight/acpi_video0 > 2) What is the output of "ls /sys/class/backlight" after > commit 965736ee654d ? no devices show up there. > 3) Can you start a kernel with commit 965736ee654d in there and > "video.only_lcd=3D0" on the kernel commandline and verify that > this fixes backlight control for you ? Confirmed, acpi_video0 shows up and backlight control works as expected. Cheers James --BOKacYhQ+x31HxR3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEd80NauSabkiESfLYbAtpk944dnoFAlrUnsYACgkQbAtpk944 dnpGlxAAkoxr01uGlwNh64cbZGZLrPZmQJykYa2sBkHQhxfBw9S6o77mGW7WTWfp PJfAEpUkm4QHdUvDgXhfs9pQfvD9xeivghqJeVCD+oz+UPAtGpNcYXU5uSge6+Zh ewF94K8I/R9Y6w5m2denQANmZVyZcDhWOaZii+bhyVqBBtwqju4nJEhN3pnMg1/F avTcCAWk62OLB10HoAByl7y6Sd0xRvP8LpTARFCcdcLq+bDqkJvSNfn05gyEzJeQ Xi/pzBpCjf0itTmvefjazkhi0JweaDgBQdPQWaEopeYZiaTdX+A+vSOSdhGI3ECy H1NNJGHW5y7MuAhZ8xKOq4ZJh4oJsMKXMl7fcFOUEpcJFTvMhekOkEXRFEzzhRIz i8K9Zffg5nU5p+2gN9mwQGqg1PJCsbEiSIM2g9MMxrqH23he4Pm8FXN7nsWR3bRL 77pyAhDUn0rLftebV3rWuwk30q1gh0WWW1r7GyKPk/BML4WSkqbZJ6OhrI9PEZpm 5tu/ct81L+gH/2OJ9iQZw26Cn/kQBm7GfVO7T6yO1DXAEMMAqYptRMqoT4hRQQCV v0MFV/kj4LPB4OHY2lAEDKyhWSraUm3eEme+iRZ5v6ULYbjof9I8tHLM/Ib9KYIS AUlxetKWZJmnX7fB6gugexGlAmxN1HfBoUjR/9EJVbILpdzzA74= =l+Mf -----END PGP SIGNATURE----- --BOKacYhQ+x31HxR3--