# Re: How to use backlight device with fb device

- From: Florian Tobias Schandinat \<FlorianSchandinat@gmx.de\>
- Date: 2011-09-15 08:58:20 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2011/09/13461979
- Thread: https://ratatoskr.run/linux-fbdev/2011/09/13461978/t.md

```text
Hi Tomi,

On 09/15/2011 07:47 AM, Tomi Valkeinen wrote:
> Hi,
> 
> I'm a bit confused how a backlight device and a fb device should be
> "connected".
> 
> In this particular case the OMAP 4430SDP board has an LCD panel
> controlled by omapfb (and omapdss on the lower level) with a backlight
> controlled by pwm_backlight (and twl6030-pwm on the lower level).
> 
> Both omapfb and pwm_backlight work fine, but they don't know anything
> about each other, so, for example, blanking the fb via omapfb leaves the
> backlight on.
> 
> Is there something I'm missing, or is the only solution to have some
> custom code to connect the fb and the bl, and handle it that way?

I don't know anything about backlight but recently there was a patch that
affected the same area you mention so it might give an idea
"[PATCH] FB: add early fb blank feature."
http://marc.info/?l=linux-fbdev&m1554458720940&w=2


Best regards,

Florian Tobias Schandinat

> 
>  Tomi
> 
> 
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```