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2025-09-03drm: panel-backlight-quirks: Add brightness mask quirkAntheas Kapenekakis
Certain OLED devices malfunction on specific brightness levels. Specifically, when DP_SOURCE_BACKLIGHT_LEVEL is written to with the first byte being 0x00 and sometimes 0x01, the panel forcibly turns off until the device sleeps again. Below are some examples. This was found by iterating over brighness ranges while printing DP_SOURCE_BACKLIGHT_LEVEL. It was found that the screen would malfunction on specific values, and some of them were collected. Therefore, introduce a quirk where the minor byte of brightness is OR'd with 0x03 to avoid the range of invalid values. This quirk was tested by removing the workarounds and iterating from 0 to 50_000 value ranges with a cadence of 0.2s/it. The range of the panel is 1000...400_000, so the values were slightly interpolated during testing. The custom brightness curve added on 6.15 was disabled. 86016: 10101000000000000 86272: 10101000100000000 87808: 10101011100000000 251648: 111101011100000000 251649: 111101011100000001 86144: 10101000010000000 87809: 10101011100000001 251650: 111101011100000010 Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3803 Tested-by: Philip Müller <philm@manjaro.org> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev> Link: https://lore.kernel.org/r/20250829145541.512671-5-lkml@antheas.dev Acked-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2025-09-03drm: panel-backlight-quirks: Convert brightness quirk to generic structureAntheas Kapenekakis
Currently, the brightness quirk is limited to minimum brightness only. Refactor it to a structure, so that more quirks can be added in the future. Reserve 0 value for "no quirk", and use u16 to allow minimum brightness up to 255. Tested-by: Philip Müller <philm@manjaro.org> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev> Link: https://lore.kernel.org/r/20250829145541.512671-3-lkml@antheas.dev Acked-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
2024-11-21drm: Add panel backlight quirksThomas Weißschuh
Panels using a PWM-controlled backlight source do not have a standard way to communicate their valid PWM ranges. On x86 the ranges are read from ACPI through driver-specific tables. The built-in ranges are not necessarily correct, or may grow stale if an older device can be retrofitted with newer panels. Add a quirk infrastructure with which the minimum valid backlight value can be maintained as part of the kernel. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Tested-by: Dustin L. Howett <dustin@howett.net> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Reviewed-by: Harry Wentland <harry.wentland@amd.com> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20241111-amdgpu-min-backlight-quirk-v7-1-f662851fda69@weissschuh.net
2019-03-07drm: export drm_timeout_abs_to_jiffiesQiang Yu
For other driver like lima usage. Cc: Rob Herring <robh@kernel.org> Signed-off-by: Qiang Yu <yuq825@gmail.com> Signed-off-by: Rob Herring <robh@kernel.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190225140717.20586-2-yuq825@gmail.com
2017-12-04drm: Add panel orientation quirks, v6.Hans de Goede
Some x86 clamshell design devices use portrait tablet screens and a display engine which cannot rotate in hardware, so the firmware just leaves things as is and we cannot figure out that the display is oriented non upright from the hardware. So at least on x86, we need a quirk table for this. This commit adds a DMI based quirk table which is initially populated with 5 such devices: Asus T100HA, GPD Pocket, GPD win, I.T.Works TW891 and the VIOS LTH17. This quirk table will be used by the drm code to let userspace know that the display is not mounted upright inside the devices case through a new panel orientation drm-connector property, as well as to tell fbcon to rotate the console so that it shows the right way up. Changes in v5: -Add a kernel-doc comment documenting drm_get_panel_orientation_quirk() -Remove board_* matches from the dmi-matches for the VIOS LTH17 laptop, keeping only the (identical) sys_vendor and product_name matches. This is necessary because an older version of the bios has board_vendor set to VOIS instead of VIOS Changes in v6: -Add reference to added kernel-docs in Documentation/gpu/drm-kms-helpers.rst Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20171125193553.23986-3-hdegoede@redhat.com