From mboxrd@z Thu Jan 1 00:00:00 1970 From: joeyli Subject: Re: PROBLEM: Acer D255E Backlight out for 10 seconds with ACPI Date: Sat, 29 Sep 2012 07:58:17 +0800 Message-ID: <1348876697.8621.135.camel@linux-s257.site> References: <1348701543.8621.104.camel@linux-s257.site> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from smtp.nue.novell.com ([195.135.221.5]:40664 "EHLO smtp.nue.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759086Ab2I2AYu (ORCPT ); Fri, 28 Sep 2012 20:24:50 -0400 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Dan Cc: linux-acpi@vger.kernel.org Hi Dan,=20 =E6=96=BC =E5=9B=9B=EF=BC=8C2012-09-27 =E6=96=BC 14:09 -0400=EF=BC=8CDa= n =E6=8F=90=E5=88=B0=EF=BC=9A > On Wed, Sep 26, 2012 at 7:19 PM, joeyli wrote: > > =E6=96=BC =E4=B8=89=EF=BC=8C2012-09-26 =E6=96=BC 16:48 -0400=EF=BC=8C= Dan =E6=8F=90=E5=88=B0=EF=BC=9A > >> Hello, > >> > >> Apologies if this was sent to the wrong place. > >> > >> With an Acer AOD255E netbook, the backlight goes out for exactly 1= 0 > >> 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=3Doff" appended to the kernel line, this no longer occu= rs (Fn > >> key backlight controls still work with this appended). With every It's a clue for that problem is happen in acpi, but sometimes the Fn ke= y on notebook is changed by BIOS, need check DSDT.=20 > >> other acpi option I have tried, this still occurs though. This > >> includes "acpi_backlight" and "acpi_display_output". With > >> "acpi_backlight=3Dvendor" the entry in /sys/class/backlight change= s 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=3D0 > > > > > > Thanks > > Joey Lee > > >=20 > Same results with that kernel parameter applied. >=20 This parameter works when _BQC used indexed value but not direct use brightness value. One possible thing is BIOS really set the initial index or brightness level to lowest level. > 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 scree= n > 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 tim= e > 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. >=20 > Once the backlight is out, it will stay out for exactly 10 seconds > before returning no matter what is on the screen. >=20 What's your value of max brightness? Please run: # cat /sys/class/backlight/acpi_video0/max_brightness Please also manually change brightness level after your system boot finished, and look at does it changed or have problem like reversed? # echo 10 > /sys/class/backlight/acpi_video0/brightness And,=20 Please attached your acpidump: # acpidump > acpidump.dat Thanks Joey Lee -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html