GTA01V3/V4 LCD framebuffer problem

[Nils Faerber]

Pierre Hébert schrieb:
> Hi,
Hi!

> On Thursday 19 July 2007, Nils Faerber wrote:
>> Hi!
>> I am currently trying to get suspend/resume working with the current
>> NEO GTA01 devices and encountered a strange issue...
>>
>> With the latest kernel 2.6.21.5 I can successfully suspend and resume
>> the machine. Most devices seem to be fine after resume, including USB,
>> audio, touchscreen, modem, etc.
>> But the LCD just displays a blank white screen with backlight switched
>> on. And this does not change anymore until reboot.
> I don't know if it can help but I had the same problem on a s3c2440 and 
> 2.6.19. In my case I found that clkdiv was wrongly computed upon resume. 
> I was not able to discover the root cause, I just used a ** really ** 
> bad hack like this :
> diff -Nurp linux-2.6.19/drivers/video/s3c2410fb.c 
> linux-2.6.19-g500/drivers/video/s3c2410fb.c
> --- linux-2.6.19/drivers/video/s3c2410fb.c  2006-11-29 22:57:37.000000000 
> +0100
> +++ linux-2.6.19-g500/drivers/video/s3c2410fb.c 2006-12-19 
> 21:21:23.000000000 +0100
> @@ -287,12 +287,15 @@ static void s3c2410fb_activate_var(struc
>   fbi->regs.lcdcon3 |=  S3C2410_LCDCON3_HOZVAL(var->xres - 1);
> 
>   if (var->pixclock > 0) {
> +#if 0
>     int clkdiv = s3c2410fb_calc_pixclk(fbi, var->pixclock);
> 
>     clkdiv = (clkdiv / 2) -1;
>     if (clkdiv < 0)
>       clkdiv = 0;
> -
> +#else
> +    int clkdiv=4;
> +#endif
>     fbi->regs.lcdcon1 &= ~S3C2410_LCDCON1_CLKVAL(0x3ff);
>     fbi->regs.lcdcon1 |=  S3C2410_LCDCON1_CLKVAL(clkdiv);
>   }
> 
> (sorry for cut&paste the diff, it is just for the example)
> I hope this can help, cheers.

Good try!

Tried this with the 2.6.21.5 kernel for NEO but it does not help :(
(Admittedly I also did not check the clkdiv values before and after
resume, maybe I will do that next).

But anyway, many thanks for looking into the problem and digging up the
patch!

> Pierre.
Cheers
  nils faerber

-- 
kernel concepts GbR      Tel: +49-271-771091-12
Sieghuetter Hauptweg 48  Fax: +49-271-771091-19
D-57072 Siegen           Mob: +49-176-21024535
--