GTA01V3/V4 LCD framebuffer problem
Nils Faerber
nils.faerber at kernelconcepts.de
Fri Jul 20 02:04:45 CEST 2007
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
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