https://bugzilla.kernel.org/show_bug.cgi?id=214899 Hans de Goede (jwrdegoede@xxxxxxxxxxxxxxxxx) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jwrdegoede@xxxxxxxxxxxxxxxx | |g --- Comment #2 from Hans de Goede (jwrdegoede@xxxxxxxxxxxxxxxxx) --- What is your kernel commandline? According to your attached dmesg it is empty, but that seems unlikely... ? The ideapad-laptop code has this: if (acpi_video_get_backlight_type() == acpi_backlight_vendor) { err = ideapad_backlight_init(priv); if (err && err != -ENODEV) goto backlight_failed; } And acpi_video_get_backlight_type() is: enum acpi_backlight_type acpi_video_get_backlight_type(void) { ... if (acpi_backlight_cmdline != acpi_backlight_undef) return acpi_backlight_cmdline; if (acpi_backlight_dmi != acpi_backlight_undef) return acpi_backlight_dmi; if (!(video_caps & ACPI_VIDEO_BACKLIGHT)) return acpi_backlight_vendor; if (acpi_osi_is_win8() && backlight_device_get_by_type(BACKLIGHT_RAW)) return acpi_backlight_native; return acpi_backlight_video; } So the only way that the ideapad backlight can get registered is if: 1. You have acpi_backlight=vendor on your kernel cmdline 2. There is a DMI quirk setting for your model in the kernel which there is not. 3. Your ACPI tables do not implement the ACPI_VIDEO_BACKLIGHT interface, but your dmesg says: [ 2.237329] ACPI: video: Video Device [GFX0] (multi-head: yes rom: no post: no) So this is unlikely, it is still possible though that your DSDT implements the ACPI video interface but not the backlight part (that would be a first). I cannot tell since the ACPI video interface is not in the DSDT, it is likely defined in one of the SSDT tables. Please attach a full acpidump. Can you try specifying: "acpi_backlight=video" on the kernel commandline and then do: ls /sys/class/backlight And copy and paste the output here. This cmdline option not only helps me debug this, but it should also workaround your backlight issue :) -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
