[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
** Changed in: linux-lts-saucy (Ubuntu) Status: Confirmed = Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
Lenovo T540p also got fixed by upgrading to the specified BIOS version, tested on 12.04.4 . -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
** Changed in: linux-lts-raring (Ubuntu) Status: Triaged = Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
Brightness auto dim and brightness testing both work now, after BIOS upgrade, as Chih mentioned in comment #22 . -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
Confirmed with the test BIOS - GNET62M1.CAP, it fixes this very issue on W540. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
A equivalent to INF flag in Linux is to use kernel parameter acpi_backlight=vendor -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
Lenovo BIOS engineer commented on Mar. 19 as:
//
I understand the situation. Since ThinkPad BIOS assumes that Windows 8
or later OS always uses the OS-driver initiated brightness control
method, so the brightness logic won't work if an OS declares it is Win8
but it uses OS-BIOS initiated brightness control method.
To workaround this, it would be better to change ASL code as below,
because BRNS() is only designed for 16-step brightness.
Please note that it is just a quick W/A.
If Linux Intel IGD driver has an option to change its behavior to OS-
driver initiated brightness control method as well as real Win8, it
would be easier.
Windows Intel IGD driver can change it to OS-driver mode with Bit8 of
FeatureTestControl = 0 in INF file.
External( \_SB.PCI0.LPC.EC.BRCD, MethodObj )
Method ( _BCM, 1 ) {
If ( \WIN8 ) {
\_SB.PCI0.VID.AINT( 1, \_SB.PCI0.LPC.EC.BRCD( Arg0 ) )
} Else {
Store( Match( \_SB.PCI0.LPC.EC.BRTW, MEQ, Arg0, MTR, 0, 2 ),
Local0 )
If( LNotEqual( Local0, Ones ) ){ // OS
requested value is found and we got index
Subtract (Local0, 2, Local1)
Store( Local1 , \BRLV )
\_SB.PCI0.LPC.EC.BRNS( )
\UCMS( TOGGLE_BIT_AND_UPDATE_CMOS )
}
}
** Attachment added: code-changes.PNG
https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+attachment/4033205/+files/code-changes.PNG
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1270079
Title:
[Lenovo T540p, W540] Backlight interfaces not fully working
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
BIOS upgrade is impossible in the official way without a battery pack. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
Some additional information to #12:
The original code is as below, and it checks BRTW as in #12
Method (_BCM, 1, NotSerialized)
{
Store (Match (\_SB.PCI0.LPC.EC.BRTW, MEQ, Arg0, MTR, 0x00, 0x02),
Local0)
If (LNotEqual (Local0, Ones))
{
Subtract (Local0, 0x02, Local1)
Store (Local1, \BRLV)
\_SB.PCI0.LPC.EC.BRNS (\UCMS (0x16))
}
}
It can be done by modifying it to something like below:
Method (_BCM, 1, NotSerialized)
{
Subtract (Local0, 0x02, Local1)
Store (Local1, \BRLV)
\_SB.PCI0.LPC.EC.BRNS (\UCMS (0x16))
}
This will ignore the table comparing.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1270079
Title:
[Lenovo T540p, W540] Backlight interfaces not fully working
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
OEM BIOS engineer has given the following feedback on Mar. 18: // It should not be removed, since it is the key process to convert OS brightness percentage (0-100) to the actual LCD PWM brightness duty value (0-255) along with the brightness curves which are defined for each LCD panels. If you remove it, the brightness function will break on Windows 7. The available brightness percentage values are defined in ACPI _BCL. Linux driver should only use the values defined in _BCL. Please see Appendix: Video Extensions chapter in ACPI spec. B.5.3 _BCM (Set the Brightness Level) This method allows OSPM to set the brightness level of a built-in display output device. The OS will only set levels that were reported via the _BCL method. This method is required if _BCL is implemented. Best Regards, Norihito Ishida // -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
I am very certain that Linux uses _BCL correctly. I think this bug is related to _OSI(Windows 2012) which is supported in kernel 3.7 or later. Some detection may be added to address the issue with Win7. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
** Changed in: linux-lts-raring (Ubuntu) Assignee: AceLan Kao (acelankao) = Alex Hung (alexhung) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
With kernel 3.11.0-17-generic, _BCL returns as below:
[ 4792.647432] Brightness[0] = 100
[ 4792.647439] Brightness[1] = 100
[ 4792.647442] Brightness[2] = 0
[ 4792.647445] Brightness[3] = 1
[ 4792.647447] Brightness[4] = 2
[ 4792.647450] Brightness[5] = 3
[ 4792.647452] Brightness[6] = 4
[ 4792.647454] Brightness[7] = 5
[ 4792.647456] Brightness[8] = 6
[ 4792.647459] Brightness[9] = 7
[ 4792.647461] Brightness[10] = 8
[ 4792.647464] Brightness[11] = 9
[ 4792.647466] Brightness[12] = 10
[ 4792.647469] Brightness[13] = 11
[ 4792.647471] Brightness[14] = 12
[ 4792.647474] Brightness[15] = 13
[ 4792.647476] Brightness[16] = 14
[ 4792.647478] Brightness[17] = 15
[ 4792.647481] Brightness[18] = 16
// skip the middle
[ 4792.647653] Brightness[92] = 90
[ 4792.647655] Brightness[93] = 91
[ 4792.647657] Brightness[94] = 92
[ 4792.647660] Brightness[95] = 93
[ 4792.647662] Brightness[96] = 94
[ 4792.647664] Brightness[97] = 95
[ 4792.647667] Brightness[98] = 96
[ 4792.647669] Brightness[99] = 97
[ 4792.647671] Brightness[100] = 98
[ 4792.647674] Brightness[101] = 99
[ 4792.647676] Brightness[102] = 100
This is the result of _OSI(Windows 2012) = true and therefore WIN8 =
1 in BIOS's ASL code. This also means that Linux kernel does not use
_BCL incorrectly (just to clarify #18).
In order to not to break original function in Win7, BIOS can be modified
as below
Method (_BCM, 1, NotSerialized)
{
If (\WIN8) // does not check BRTW for WIN8 or later.
{
Subtract (Local0, 0x02, Local1)
Store (Local1, \BRLV)
\_SB.PCI0.LPC.EC.BRNS (\UCMS (0x16))
}
else
{
Store (Match (\_SB.PCI0.LPC.EC.BRTW, MEQ, Arg0, MTR, 0x00,
0x02), Local0)
If (LNotEqual (Local0, Ones))
{
Subtract (Local0, 0x02, Local1)
Store (Local1, \BRLV)
\_SB.PCI0.LPC.EC.BRNS (\UCMS (0x16))
}
}
}
Alternatively, BIOS can also have WIN8 detection for BRTW, ex. returns
0~100 if WIN8 = 1 annd _BCM can stay unchanged.
** Changed in: linux-lts-raring (Ubuntu)
Status: Confirmed = Triaged
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1270079
Title:
[Lenovo T540p, W540] Backlight interfaces not fully working
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
@Alex, could you please let me know which BIOS version that you are working on? Is it GNET58WW (2.06)? I'll escalate to Lenovo, thank you! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
Status changed to 'Confirmed' because the bug affects multiple users. ** Changed in: linux-lts-saucy (Ubuntu) Status: New = Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
Status changed to 'Confirmed' because the bug affects multiple users. ** Changed in: linux-lts-raring (Ubuntu) Status: New = Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
From BIOS AML, the brightness function (ex. _BCM) checks a table before
making actual brightness adjustment. The table is located in DSDT and
attached below:
Name (BRTW, Package (0x12)
{
0x64,
0x64,
0x01,
0x03,
0x05,
0x08,
0x0C,
0x11,
0x16,
0x21,
0x28,
0x2E,
0x36,
0x3E,
0x47,
0x50,
0x5A,
0x64
})
This looks like a BIOS design. We need a BIOS update to remove the
comparison to the table. Kernel cannot work around this bug at all
except removing the uses of ACPI backlight control.
There is no harm to remove the comparison for Windows 8 as it does not
calls _BCM for brightness.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1270079
Title:
[Lenovo T540p, W540] Backlight interfaces not fully working
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
** Attachment added: acpi.log https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+attachment/4006466/+files/acpi.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
There is a new BIOS released on 2/19, but the BIOS CD image seems can't boot directly from USB disk. Sorry, I have no time to study it, will let Yung help on this. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
** Also affects: linux-lts-saucy (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
** Changed in: linux-lts-saucy (Ubuntu) Importance: Undecided = High -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
We later found that the backlight adjustment (using hotkeys) work normally after enabling the W540's discrete nVidia GPU (through installing nvidia-prime and nvidia-331 packages.) in Ubuntu 12.04.4. @Acelan, does this suggest that to disable the ACPI backlight interface on these systems in the patch you mentioned would also work in Intel's case when applied? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
According to comment #4 , Tried upgrading W540 BIOS firmware from GNET22WW (1.04 ) to GNET58WW (2.06) but brightness key still not working. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
An updated BIOS (1.12) is available at official Lenovo site: http://support.lenovo.com/en_US/downloads/detail.page?DocID=DS039066 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
additional note, there are two testcases will be effected by this issue: 1. The brightness keys 2.Dim screen to save power, that system will dim screen automatically when it's on battery. and the second test is a blocker to the certification test, which caused by backlight interfaces not fully function. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
This issue could be fixed by kernel after the below 2 patches are accepted. I think the second one is still in drm-intel-nightly git tree. http://lists.freedesktop.org/archives/dri-devel/2013-September/045421.html http://www.spinics.net/lists/linux-acpi/msg47755.html -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
I've double check this issue with different kernel parameters, by adding following parameter, the brightness keys and the dim_brightness test now works fine, even OSD can response correctly. acpi_osi='!Windows 2012' but this is still an issue, since changing parameters in /etc/default/grub will not pass the certification test. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
According to Yung's comment on #3, the Windows 2012 means Windows 8 and Server 2012 The linux kernel will tell the BIOS we are Win8 after kernel 3.7, the kernel parameter in #3 tells the BIOS that we are Win7. So, it looks like it's a BIOS issue that has different behavior on Win7 and Win8. We can try to use the newer version of BIOS to see if it can fix this issue. Other solutions are all workarounds. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
@AceLan, hi acelan, please help to take a look at this issue ** Changed in: linux-lts-raring (Ubuntu) Assignee: (unassigned) = AceLan Kao (acelankao) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1270079] Re: [Lenovo T540p, W540] Backlight interfaces not fully working
** Changed in: linux-lts-raring (Ubuntu) Importance: Undecided = Medium -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
