[maemo-developers] Does anyone know the mechanism in Nokia's LCD driver?

[From: Huang Gao (Gmail)]

Hi, Frantisek:
	I now understand.
	Thank you for your explanation!

Best Regards
Huang Gao(黄杲)

-----邮件原件-----
发件人: Frantisek Dufka [mailto:dufkaf at seznam.cz] 
发送时间: 2009年1月13日 18:49
收件人: ext Huang Gao (Gmail)
抄送: igor.stoppa at nokia.com; maemo-developers at maemo.org
主题: Re: Does anyone know the mechanism in Nokia's LCD driver?

Igor Stoppa wrote:
> Hi,
> On Tue, 2009-01-13 at 18:06 +0800, ext Huang Gao (Gmail) wrote:
>> 	So can I understand that this hardware FB is not contained in SDRAM
>> or SRAM, and LCD will refresh itself from this hardware FB by its
controller
>> automatically, without the help of OMAP DMA channel?

Yes. The Epson S1D13742 (770) or S1D13745 (N8x0) lcd controller has its 
own video RAM.

> 
> I'm in no way a display guy but iirc there are 2 modes for refresh:
> -auto: whatever is written to the framebuffer goes through straight to
> the LCD
> -manual: the image needs to be flushed to the LCD

Well, both modes use same way for transferring data to LCD, the only 
difference is when the update is done. Either periodically from timer or 
when update ioctl is called.

The source is here
http://mxr.maemo.org/diablo/source/kernel-source-diablo-2.6.21/kernel-source
/drivers/video/omap/
see omapfb_main, rfbi (n8x0) or sossi (770), blizzard (N8x0) or hwa742 
(770), lcd_mipid.

Frantisek