Re: KMS Framebuffer on Intel N2600 (GMA3600)

[Forconi <forconi@wavecomm.it>]

Hi Alan,
thanks again for your answer.

Reading the manual of the board I found this specification:
LVDS: 24-bit dual channel via CH7511 thru eDP

The Chrontel CH7511 is a DisplayPort (DP/eDP) to LVDS converter.

So, what I understand is that the LVDS interface that comes out
from the connector on the board is connected to the CH7511 that
is connected to the DP/eDP port on the CPU.

Until now I was starting the kernel with video=LVDS-1.....,
maybe I have to use another video device like DVI to use the eDP port?



Regards,
Samuele.



----- Messaggio originale -----
Da: "Alan Cox" <alan@lxorguk.ukuu.org.uk>
A: "Forconi" <forconi@wavecomm.it>
Cc: linux-kernel@vger.kernel.org
Inviato: Mercoledì, 14 novembre 2012 18:17:55
Oggetto: Re: KMS Framebuffer on Intel N2600 (GMA3600)

> This backlight problem appears only when I run linux with KMS framebuffer,
> when I run linux without KMS framebuffer, the backlight is always on.
> 
> Yes, I have ACPI enabled and ACPI backlight enabled, but running:
> echo 100 > /sys/class/backlight/psb-bl/brightness

psb-bl/backlight willbe the backlight of the graphics not the ACPI
driver. You may need to enable that and also hack the acpi_video code to
add it anyway on that device.

> But, in the end, this means that the driver si correctly loaded and the 
> framebuffer is running but the panel backlight is off?
> In other words, I can't see anything only because the backlight is off?

I think so.

> I don't know which could be the maximum value, there are any standard values
> for backlight settings? I could try setting some values and see what happens...

Unfortunately not - and I have no idea what overdriving it would do to
the hardware.

Alan

-- 
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