On Wed, Sep 26, 2012 at 7:19 PM, joeyli <jlee@xxxxxxxx> wrote: > 於 三，2012-09-26 於 16:48 -0400，Dan 提到： >> Hello, >> >> Apologies if this was sent to the wrong place. >> >> With an Acer AOD255E netbook, the backlight goes out for exactly 10 >> seconds before returning while booting. >> >> This is a backlight issue and not KMS, as I can shine a flashlight at >> the screen and still see boot text scrolling. >> >> With "acpi=off" appended to the kernel line, this no longer occurs (Fn >> key backlight controls still work with this appended). With every >> other acpi option I have tried, this still occurs though. This >> includes "acpi_backlight" and "acpi_display_output". With >> "acpi_backlight=vendor" the entry in /sys/class/backlight changes from >> acpi_video0 to acer_wmi, but backlight still goes out. >> >> Otherwise backlight works correctly. > > Could you please try this kernel parameter? > video.use_bios_initial_backlight=0 > > > Thanks > Joey Lee > Same results with that kernel parameter applied. Just to make it clear when this is happening: The BIOS screen and bootloader work fine. This occurs during the boot process while the systemd text is scrolling (or with the splash screen in the case of Ubuntu). I have not been able to pin down any event during the boot process that triggers it. It seems to be based on time after the kernel loads. I can tell by the difference booting from a HDD vs a SSD. With a HDD, it will occur earlier in the process (close to the time init is called) since booting takes longer. With an SSD, the backlight goes out close to the time the login screen appears. Once the backlight is out, it will stay out for exactly 10 seconds before returning no matter what is on the screen. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
