From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Hans de Goede <hdegoede@redhat.com>
Cc: "Karol Herbst" <kherbst@redhat.com>,
"Daniel Dadap" <ddadap@nvidia.com>,
nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
platform-driver-x86@vger.kernel.org,
"Dmitry Osipenko" <digetx@gmail.com>,
"Rafael J . Wysocki" <rafael@kernel.org>,
amd-gfx@lists.freedesktop.org, linux-acpi@vger.kernel.org,
"Ben Skeggs" <bskeggs@redhat.com>,
"David Airlie" <airlied@redhat.com>,
"Len Brown" <lenb@kernel.org>,
"Matthew Garrett" <mjg59@srcf.ucam.org>,
"Jani Nikula" <jani.nikula@intel.com>,
intel-gfx <intel-gfx@lists.freedesktop.org>,
"Mark Gross" <markgross@kernel.org>,
"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
"Mika Westerberg" <mika.westerberg@linux.intel.com>,
"Andy Shevchenko" <andy@kernel.org>,
"Tvrtko Ursulin" <tvrtko.ursulin@linux.intel.com>,
Xinhui <Xinhui.Pan@amd.com>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Christian König" <christian.koenig@amd.com>
Subject: Re: [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2)
Date: Thu, 27 Oct 2022 14:09:27 +0200 [thread overview]
Message-ID: <CAJZ5v0jM1JAySagv=u2be1bAmfTt3jJgVnOEjGzskBvZY7k6aw@mail.gmail.com> (raw)
In-Reply-To: <6df2016d-ed2d-57fa-dcad-48537732895f@redhat.com>
On Thu, Oct 27, 2022 at 12:37 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi,
>
> On 10/27/22 11:52, Matthew Garrett wrote:
> > On Thu, Oct 27, 2022 at 11:39:38AM +0200, Hans de Goede wrote:
> >
> >> The *only* behavior which actually is new in 6.1 is the native GPU
> >> drivers now doing the equivalent of:
> >>
> >> if (acpi_video_get_backlight_type() != acpi_backlight_native)
> >> return;
> >>
> >> In their backlight register paths (i), which is causing the native
> >> backlight to disappear on your custom laptop setup and on Chromebooks
> >> (with the Chromebooks case being already solved I hope.).
> >
> > It's causing the backlight control to vanish on any machine that isn't
> > ((acpi_video || vendor interface) || !acpi). Most machines that fall
> > into that are either weird or Chromebooks or old, but there are machines
> > that fall into that.
>
> I acknowledge that their are machines that fall into this category,
> but I expect / hope there to be so few of them that we can just DMI
> quirk our way out if this.
>
> I believe the old group to be small because:
>
> 1. Generally speaking the "native" control method is usually not
> present on the really old (pre ACPI video spec) mobile GPUs.
>
> 2. On most old laptops I would still expect there to be a vendor
> interface too, and if both get registered standard desktop environments
> will prefer the vendor one, so then we need a native DMI quirk to
> disable the vendor interface anyways and we already have a bunch of
> those, so some laptops in this group are already covered by DMI quirks.
>
> And a fix for the Chromebook case is already in Linus' tree, which
> just leaves the weird case, of which there will hopefully be only
> a few.
>
> I do share your worry that this might break some machines, but
> the only way to really find out is to get this code out there
> I'm afraid.
>
> I have just written a blog post asking for people to check if
> their laptop might be affected; and to report various details
> to me of their laptop is affected:
>
> https://hansdegoede.dreamwidth.org/26548.html
>
> Lets wait and see how this goes. If I get (too) many reports then
> I will send a revert of the addition of the:
>
> if (acpi_video_get_backlight_type() != acpi_backlight_native)
> return;
>
> check to the i915 / radeon / amd / nouveau drivers.
>
> (And if I only get a couple of reports I will probably just submit
> DMI quirks for the affected models).
Sounds reasonable to me, FWIW.
And IIUC the check above can be overridden by passing
acpi_backlight=native in the kernel command line, right?
next prev parent reply other threads:[~2022-10-27 12:09 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-25 14:36 [PATCH v5 00/31] drm/kms: Stop registering multiple /sys/class/backlight devs for a single display Hans de Goede
2022-08-25 14:36 ` [PATCH v5 01/31] ACPI: video: Add acpi_video_backlight_use_native() helper Hans de Goede
2022-08-25 14:36 ` [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2) Hans de Goede
2022-09-25 23:39 ` Dmitry Osipenko
2022-09-27 11:04 ` Hans de Goede
2022-10-24 20:30 ` Matthew Garrett
2022-10-25 18:50 ` Hans de Goede
2022-10-25 19:32 ` Matthew Garrett
2022-10-25 20:25 ` Hans de Goede
2022-10-25 20:31 ` Limonciello, Mario
2022-10-25 20:32 ` Hans de Goede
2022-10-25 20:40 ` Matthew Garrett
2022-10-25 23:27 ` Hans de Goede
2022-10-25 23:40 ` Matthew Garrett
2022-10-26 9:59 ` Hans de Goede
2022-10-26 20:49 ` Matthew Garrett
2022-10-27 8:51 ` Hans de Goede
2022-10-27 9:11 ` Matthew Garrett
2022-10-27 9:39 ` Hans de Goede
2022-10-27 9:52 ` Matthew Garrett
2022-10-27 10:37 ` Hans de Goede
2022-10-27 12:09 ` Rafael J. Wysocki [this message]
2022-10-27 12:17 ` Hans de Goede
2022-10-27 12:19 ` Rafael J. Wysocki
2022-11-04 16:23 ` Hans de Goede
2022-08-25 14:36 ` [PATCH v5 03/31] drm/amdgpu: Don't register backlight when another backlight should be used (v3) Hans de Goede
2022-08-25 14:36 ` [PATCH v5 04/31] drm/radeon: " Hans de Goede
2022-08-25 14:37 ` [PATCH v5 05/31] drm/nouveau: Don't register backlight when another backlight should be used (v2) Hans de Goede
2022-08-25 14:37 ` [PATCH v5 06/31] ACPI: video: Drop backlight_device_get_by_type() call from acpi_video_get_backlight_type() Hans de Goede
2022-08-25 14:37 ` [PATCH v5 07/31] ACPI: video: Remove acpi_video_bus from list before tearing it down Hans de Goede
2022-08-25 14:37 ` [PATCH v5 08/31] ACPI: video: Simplify acpi_video_unregister_backlight() Hans de Goede
2022-08-25 14:37 ` [PATCH v5 09/31] ACPI: video: Make backlight class device registration a separate step (v2) Hans de Goede
2022-08-25 14:37 ` [PATCH v5 10/31] ACPI: video: Remove code to unregister acpi_video backlight when a native backlight registers Hans de Goede
2022-08-25 14:37 ` [PATCH v5 11/31] drm/i915: Call acpi_video_register_backlight() (v3) Hans de Goede
2022-09-02 13:20 ` Jani Nikula
2022-08-25 14:37 ` [PATCH v5 12/31] drm/nouveau: Register ACPI video backlight when nv_backlight registration fails (v2) Hans de Goede
2022-08-25 14:37 ` [PATCH v5 13/31] drm/amdgpu: Register ACPI video backlight when skipping amdgpu backlight registration Hans de Goede
2022-08-25 14:37 ` [PATCH v5 14/31] drm/radeon: Register ACPI video backlight when skipping radeon " Hans de Goede
2022-08-25 14:37 ` [PATCH v5 15/31] platform/x86: nvidia-wmi-ec-backlight: Move fw interface definitions to a header (v2) Hans de Goede
2022-08-25 22:11 ` Daniel Dadap
2022-08-25 14:37 ` [PATCH v5 16/31] ACPI: video: Refactor acpi_video_get_backlight_type() a bit Hans de Goede
2022-08-25 14:37 ` [PATCH v5 17/31] ACPI: video: Add Nvidia WMI EC brightness control detection (v3) Hans de Goede
2022-08-25 22:21 ` Daniel Dadap
2022-08-29 11:41 ` Hans de Goede
2022-08-29 16:43 ` Daniel Dadap
2022-08-25 14:37 ` [PATCH v5 18/31] ACPI: video: Add Apple GMUX brightness control detection Hans de Goede
2022-08-25 14:37 ` [PATCH v5 19/31] platform/x86: nvidia-wmi-ec-backlight: Use acpi_video_get_backlight_type() Hans de Goede
2022-08-25 14:37 ` [PATCH v5 20/31] platform/x86: apple-gmux: Stop calling acpi/video.h functions Hans de Goede
2022-08-25 14:37 ` [PATCH v5 21/31] platform/x86: toshiba_acpi: Stop using acpi_video_set_dmi_backlight_type() Hans de Goede
2022-08-25 14:37 ` [PATCH v5 22/31] platform/x86: acer-wmi: Move backlight DMI quirks to acpi/video_detect.c Hans de Goede
2022-08-25 14:37 ` [PATCH v5 23/31] platform/x86: asus-wmi: Drop DMI chassis-type check from backlight handling Hans de Goede
2022-08-25 14:37 ` [PATCH v5 24/31] platform/x86: asus-wmi: Move acpi_backlight=vendor quirks to ACPI video_detect.c Hans de Goede
2022-08-25 14:37 ` [PATCH v5 25/31] platform/x86: asus-wmi: Move acpi_backlight=native " Hans de Goede
2022-08-25 14:37 ` [PATCH v5 26/31] platform/x86: samsung-laptop: Move acpi_backlight=[vendor|native] " Hans de Goede
2022-08-25 14:37 ` [PATCH v5 27/31] ACPI: video: Remove acpi_video_set_dmi_backlight_type() Hans de Goede
2022-08-25 14:37 ` [PATCH v5 28/31] ACPI: video: Drop "Samsung X360" acpi_backlight=native quirk Hans de Goede
2022-08-25 14:37 ` [PATCH v5 29/31] ACPI: video: Drop NL5x?U, PF4NU1F and PF5?U?? acpi_backlight=native quirks Hans de Goede
2022-08-25 14:37 ` [PATCH v5 30/31] ACPI: video: Fix indentation of video_detect_dmi_table[] entries Hans de Goede
2022-08-25 14:37 ` [PATCH v5 31/31] drm/todo: Add entry about dealing with brightness control on devices with > 1 panel Hans de Goede
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