[Intel-gfx] Intel Arrandale IGDNG VGA issue

[ykzhao]

On Thu, 2010-01-28 at 12:18 +0800, CSJ wrote:
> Hello,
> 

Hi, 
	Do you have an opportunity to try the 2.6.33-rc5 kernel and see whether
the issue still exists?

Thanks.
	Yakui
> I got an issue on Intel Core i5 M540 with LG panel (Max resolution is
> 1920x1080).
> That screen is fuzzy on the right area on Ubuntu as attached picture.
> 
> And after checking, the root cause is PLL setting in the Intel native
> driver.
> (drivers/gpu/drm/i915/intel_display.c)
> 
> in intel_igdng_find_best_PLL function, it goes to red lines,
> 
>                                                 continue;
>                                         this_err = abs((10000 -
> (target*10000/clock.dot)));
>                                         if (this_err < err_most) {
>                                                 *best_clock = clock;
>                                                 /* found on first
> matching */
>                                                 goto out;
>                                         } else if (this_err < err_min)
> {
>                                                 *best_clock = clock;
>                                                 err_min = this_err;
> 
> and the clock settings before function return are:
>         clock.n=6
>         clock.m1=11
>         clock.m2=4
>         clock.p1=0
>         clock.p2=7
>         clock.dot=188571
>         clock.vco=1320000
>         clock.m=77
>         clock.p=7
> the kernel version is 2.6.32.6 .
> 
> It will become terrible if I modify the clock setting
> manually(forcellu) to the values that
> from the the other machine with same chips but CMO panel (the screen
> is normal).
> (the CMO screen max resolution is 1600x900)
> 
> Is there any suggestion to tune the clock settings?
> thanks a lot :)
> 
> CSJ
> <changsijay at gmail.com>