From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Hung Subject: Re: [PATCH] acpi: fix brightness level is initialized to zero when BIOS does not restore the brightness value to _BQC. Date: Mon, 01 Oct 2012 15:03:03 +0800 Message-ID: <50694027.5060902@canonical.com> References: <1349069987-23992-1-git-send-email-alex.hung@canonical.com> <1349074033.24232.19.camel@linux-s257.site> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from youngberry.canonical.com ([91.189.89.112]:34626 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751986Ab2JAHDM (ORCPT ); Mon, 1 Oct 2012 03:03:12 -0400 In-Reply-To: <1349074033.24232.19.camel@linux-s257.site> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: joeyli Cc: rui.zhang@intel.com, linux-acpi@vger.kernel.org On 10/01/2012 02:47 PM, joeyli wrote: > Hi Alex, > > =E6=96=BC =E4=B8=80=EF=BC=8C2012-10-01 =E6=96=BC 13:39 +0800=EF=BC=8C= Alex Hung =E6=8F=90=E5=88=B0=EF=BC=9A >> Signed-off-by: Alex Hung >> --- >> drivers/acpi/video.c | 4 ++++ >> 1 files changed, 4 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c >> index 42b226e..eaa9573 100644 >> --- a/drivers/acpi/video.c >> +++ b/drivers/acpi/video.c >> @@ -724,6 +724,10 @@ acpi_video_init_brightness(struct acpi_video_de= vice *device) >> if (level_old =3D=3D br->levels[i]) >> level =3D level_old; >> } >> + >> + if (level =3D=3D 0) >> + level =3D br->levels[(br->count) / 2 + 1]; > > Looks here used the 50% brightness level. > > Per comment in video.c, we want set the backlight to max_level when > level_old is invalid: > > if (!br->flags._BQC_use_index) { > /* > * Set the backlight to the initial state. > * On some buggy laptops, _BQC returns an uninitiali= zed value > * when invoked for the first time, i.e. level_old i= s invalid. > * set the backlight to max_level in this case > */ > > I think here used max_level to fulfill it, e.g. > =09 > + if (level =3D=3D 0) > + level =3D max_level; > > How do you think? Hi Joey, I was debating with myself which level to be set, ex. 50%, ~75% or 100%= ,=20 and I think 50% *might* be closer to normal use-case (just a personal=20 guess). However, "max_level" seems to fit best if we treat the initial zero=20 brightness in invalid. I can modify it according it that's preferred. Thanks for the feedback. Cheers, Alex Hung > >> + >> goto set_level; >> } >> > > Thanks a lot! > 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