linux-kernel - Keyboard backlight not working on my NP900X5N laptop <previous not accepted due to HTML encoding>

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Date:   Tue, 1 Jan 2019 13:48:49 +0100
From:   Jan Vlietland <j.vlietland@...i.nl>
To:     Corentin Chary <corentin.chary@...il.com>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        open list <linux-kernel@...r.kernel.org>
Cc:     "open list:SAMSUNG LAPTOP DRIVER" 
        <platform-driver-x86@...r.kernel.org>
Subject: Keyboard backlight not working on my NP900X5N laptop <previous not
 accepted due to HTML encoding>

Hi all,

Greg K-H suggested to mail you guys.

I installed Linux 4.20.0-rc7 (downloaded, compiled and installed) on a Samsung NP900X5N laptop and have noticed 3 bugs. 2 of them I found in Bugzilla and replied on them (i915 and Nouveau issues). I am currently discussing them with an intel engineer.

On other bug I haven't found so therefore a mail directly to you guys as maintainers.

On my other machine, a Samsung NP900X4D (just bought it in the USA, 2017 model), the samsung-laptop.ko module is enabling the use of the keyboard backlight keys.

It is not working on my new machine NP900X5N. My samsung-laptop.ko driver isn't loading. If I try to load it manually it complains about 'no such device".

My Linux kernel is working in CSM mode. The module is still not loaded.

As it is weekend I did some more reading and debugging of the module. To my understanding the module checks the model and type of the laptop. The known models and types are stored in the struct:

static struct dmi_system_id __initdata samsung_dmi_table[]

I wondr if the NP900X5N notebook is included in this list.

With dmidecode -t chassis it shows:
Getting SMBIOS data from sysfs.
SMBIOS 3.0.0 present.

Handle 0x0003, DMI type 3, 22 bytes
Chassis Information
         Manufacturer: SAMSUNG ELECTRONICS CO., LTD.
         Type: Notebook
         Lock: Not Present
         Version: N/A
         Serial Number: 0F4C91CJ900346
         Asset Tag: No Asset Tag
         Boot-up State: Safe
         Power Supply State: Safe
         Thermal State: Other
         Security Status: None
         OEM Information: 0x00000000
         Height: Unspecified
         Number Of Power Cords: 1
         Contained Elements: 0
         SKU Number: Chassis

If I use the -u flag. The notebook value is 0x0A, not 0x10!!!

Could that be the reason for not loading?

		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR,
					"SAMSUNG ELECTRONICS CO., LTD."),
			DMI_MATCH(DMI_CHASSIS_TYPE, "10"), /* Notebook */
		},

Maybe another reason could that that either the i915 and Nouveau modules 
are not working well. I get black screens with the i915 and MMIO faults 
with the nouveau driver. That is another issue that I need to tackle.

Oh happy new year :-)

-- 

Met vriendelijke groet,

*dr. Jan Vlietland*, namens

spin-off

Nederlands Instituut voor de Software Industrie

_j.vlietland@...i.nl_| 06 – 20 411 834 | 030 – 268 53 98
Princetonplein 5 | 3584 CC  Utrecht | www.nisi.nl