kernel/linux.git/include/acpi/video.h, branch v6.6.131

ACPI: video: Remove register_backlight_delay module option and code

2023-04-11T18:55:46+00:00

Since commit 5aa9d943e9b6 ("ACPI: video: Don't enable fallback path for creating ACPI backlight by default"), the delayed registering of acpi_video# backlight devices has been disabled by default. The few bugreports where this option was used as a workaround were all cases where the GPU driver did not call acpi_video_register_backlight() and the workaround was to pass video.register_backlight_delay=1. With the recent "ACPI: video: Make acpi_backlight=video work independent from GPU driver" changes acpi_backlight=video can be used to achieve the same result. So there is no need for the register_backlight_delay option + code anymore. Reviewed-by: Mario Limonciello Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI: video: Add auto_detect arg to __acpi_video_get_backlight_type()

2023-04-05T18:23:02+00:00

Allow callers of __acpi_video_get_backlight_type() to pass a pointer to a bool which will get set to false if the backlight-type comes from the cmdline or a DMI quirk and set to true if auto-detection was used. And make __acpi_video_get_backlight_type() non static so that it can be called directly outside of video_detect.c . While at it turn the acpi_video_get_backlight_type() and acpi_video_backlight_use_native() wrappers into static inline functions in include/acpi/video.h, so that we need to export one less symbol. Fixes: 5aa9d943e9b6 ("ACPI: video: Don't enable fallback path for creating ACPI backlight by default") Cc: All applicable Reviewed-by: Mario Limonciello Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI: video: Allow GPU drivers to report no panels

2022-12-22T16:26:41+00:00

The current logic for the ACPI backlight detection will create a backlight device if no native or vendor drivers have created 8 seconds after the system has booted if the ACPI tables included backlight control methods. If the GPU drivers have loaded, they may be able to report whether any LCD panels were found. Allow using this information to factor in whether to enable the fallback logic for making an acpi_video0 backlight device. Suggested-by: Hans de Goede Signed-off-by: Mario Limonciello Reviewed-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI: video: Remove acpi_video_set_dmi_backlight_type()

2022-09-03T10:17:27+00:00

acpi_video_set_dmi_backlight_type() is troublesome because it may end up getting called after other backlight drivers have already called acpi_video_get_backlight_type() resulting in the other drivers already being registered even though they should not. In case of the acpi_video backlight, acpi_video_set_dmi_backlight_type() actually calls acpi_video_unregister_backlight() since that is often probed earlier, leading to userspace seeing the acpi_video0 class device being briefly available, leading to races in userspace where udev probe-rules try to access the device and it is already gone. All callers have been fixed to no longer call it, so remove acpi_video_set_dmi_backlight_type() now. This means we now also no longer need acpi_video_unregister_backlight() for the remove acpi_video backlight after it was wrongly registered hack, so remove that too. Acked-by: Rafael J. Wysocki Signed-off-by: Hans de Goede

ACPI: video: Add Apple GMUX brightness control detection

2022-09-03T10:17:26+00:00

On Apple laptops with an Apple GMUX using this for brightness control, should take precedence of any other brightness control methods. Add apple-gmux detection to acpi_video_get_backlight_type() using the already existing apple_gmux_present() helper function. This will allow removig the (ab)use of: acpi_video_set_dmi_backlight_type(acpi_backlight_vendor); Inside the apple-gmux driver. Acked-by: Rafael J. Wysocki Signed-off-by: Hans de Goede

ACPI: video: Add Nvidia WMI EC brightness control detection (v3)

2022-09-03T10:17:26+00:00

On some new laptop designs a new Nvidia specific WMI interface is present which gives info about panel brightness control and may allow controlling the brightness through this interface when the embedded controller is used for brightness control. When this WMI interface is present and indicates that the EC is used, then this interface should be used for brightness control. Changes in v2: - Use the new shared nvidia-wmi-ec-backlight.h header for the WMI firmware API definitions - ACPI_VIDEO can now be enabled on non X86 too, adjust the Kconfig changes to match this. Changes in v3: - Use WMI_BRIGHTNESS_GUID define Acked-by: Rafael J. Wysocki Reviewed-by: Daniel Dadap Signed-off-by: Hans de Goede

ACPI: video: Make backlight class device registration a separate step (v2)

2022-09-02T07:57:14+00:00

On x86/ACPI boards the acpi_video driver will usually initialize before the kms driver (except i915). This causes /sys/class/backlight/acpi_video0 to show up and then the kms driver registers its own native backlight device after which the drivers/acpi/video_detect.c code unregisters the acpi_video0 device (when acpi_video_get_backlight_type()==native). This means that userspace briefly sees 2 devices and the disappearing of acpi_video0 after a brief time confuses the systemd backlight level save/restore code, see e.g.: https://bbs.archlinux.org/viewtopic.php?id=269920 To fix this make backlight class device registration a separate step done by a new acpi_video_register_backlight() function. The intend is for this to be called by the drm/kms driver *after* it is done setting up its own native backlight device. So that acpi_video_get_backlight_type() knows if a native backlight will be available or not at acpi_video backlight registration time, avoiding the add + remove dance. Note the new acpi_video_register_backlight() function is also called from a delayed work to ensure that the acpi_video backlight devices does get registered if necessary even if there is no drm/kms driver or when it is disabled. Changes in v2: - Make register_backlight_delay a module parameter, mainly so that it can be disabled by Nvidia binary driver users Acked-by: Rafael J. Wysocki Signed-off-by: Hans de Goede

ACPI: video: Add acpi_video_backlight_use_native() helper

2022-08-17T10:30:05+00:00

ATM on x86 laptops where we want userspace to use the acpi_video backlight device we often register both the GPU's native backlight device and acpi_video's firmware acpi_video# backlight device. This relies on userspace preferring firmware type backlight devices over native ones, but registering 2 backlight devices for a single display really is undesirable. On x86 laptops where the native GPU backlight device should be used, the registering of other backlight devices is avoided by their drivers using acpi_video_get_backlight_type() and only registering their backlight if the return value matches their type. acpi_video_get_backlight_type() uses backlight_device_get_by_type(BACKLIGHT_RAW) to determine if a native driver is available and will never return native if this returns false. This means that the GPU's native backlight registering code cannot just call acpi_video_get_backlight_type() to determine if it should register its backlight, since acpi_video_get_backlight_type() will never return native until the native backlight has already registered. To fix this add a new internal native function parameter to acpi_video_get_backlight_type(), which when set to true will make acpi_video_get_backlight_type() behave as if a native backlight has already been registered. And add a new acpi_video_backlight_use_native() helper, which sets this to true, for use in native GPU backlight code. Changes in v2: - Replace adding a native parameter to acpi_video_get_backlight_type() with adding a new acpi_video_backlight_use_native() helper. Acked-by: Rafael J. Wysocki Signed-off-by: Hans de Goede

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

ACPI / video: Move ACPI_VIDEO_NOTIFY_* defines to acpi/video.h

2016-11-16T22:07:43+00:00

acpi_video.c passed the ACPI_VIDEO_NOTIFY_* defines as type code to acpi_notifier_call_chain(). Move these defines to acpi/video.h so that acpi_notifier listeners can check the type code using these defines. Signed-off-by: Hans de Goede Reviewed-by: Peter Wu Signed-off-by: Rafael J. Wysocki