Problems with ati driver on Tibook

[Alex Deucher]

On Sat, Jan 2, 2010 at 8:53 PM, John R. Dunning <jrd at jrd.org> wrote:
>    From: "John R. Dunning" <jrd at jrd.org>
>    Date: Mon, 28 Dec 2009 16:11:38 -0500
>
> [...]
>
> I debugged it further.
>
> The difficulty seems to show up in the code which enables/disables
> LVDS.  I looked at the more or less analogous code in the kernel
> radeon-fb driver, and cribbed what appeared to be the relevant
> sequence, resulting in the patch which is appended.  With this patch
> in place, the screen no longer does the bizarre "bloom" of backlight
> effects, and seems to behave the way I expect w/r/t the screen saver
> and powersave modes.
>
> Looking at the code, my surmise is that the problem centers around
> RADEON_LVDS_BLON vs RADEON_LVDS_BL_MOD_EN.  If I'm reading it right,
> the former is doing something I don't understand, whereas the latter
> is actually controlling the backlight, and maybe some other stuff.  I
> didn't look super hard for doc on this chipset, so I'm guessing.
>
> In any event, this seems to work for me, so I'll continue to run with
> it until further notice.  Hope it's of some use.  Thanks again for
> your help...

I'm not sure if this sequence will cause any problems on PC laptops or
not, I suppose it depends on the oem, so I've made the patch
mac-specific for now.  If the attached patch works for you, I'll go
ahead and commit it.

Thanks,

Alex


>
>
> --- xf86-video-ati-6.12.4-orig/work/xf86-video-ati-6.12.4/src/legacy_output.c   2009-09-09 22:58:47.000000000 -0400
> +++ xf86-video-ati-6.12.4/work/xf86-video-ati-6.12.4/src/legacy_output.c        2010-01-02 20:39:44.000000000 -0500
> @@ -912,6 +912,7 @@
>            ErrorF("enable LVDS\n");
>            tmp = INREG(RADEON_LVDS_GEN_CNTL);
>            tmp |= (RADEON_LVDS_ON | RADEON_LVDS_BLON | RADEON_LVDS_EN);
> +           tmp |= (RADEON_LVDS_BL_MOD_EN);
>            tmp &= ~(RADEON_LVDS_DISPLAY_DIS);
>            usleep (lvds->PanelPwrDly * 1000);
>            OUTREG(RADEON_LVDS_GEN_CNTL, tmp);
> @@ -994,6 +995,9 @@
>            case ENCODER_OBJECT_ID_INTERNAL_LVDS:
>                {
>                    unsigned long tmpPixclksCntl = INPLL(pScrn, RADEON_PIXCLKS_CNTL);
> +
> +                   tmp = INREG(RADEON_LVDS_GEN_CNTL);
> +
>                    ErrorF("disable LVDS\n");
>                    if (info->IsMobility || info->IsIGP) {
>                        /* Asic bug, when turning off LVDS_ON, we have to make sure
> @@ -1001,10 +1005,19 @@
>                        */
>                        OUTPLLP(pScrn, RADEON_PIXCLKS_CNTL, 0, ~RADEON_PIXCLK_LVDS_ALWAYS_ONb);
>                    }
> -                   tmp = INREG(RADEON_LVDS_GEN_CNTL);
> +
>                    tmp |= RADEON_LVDS_DISPLAY_DIS;
> -                   tmp &= ~(RADEON_LVDS_ON | RADEON_LVDS_BLON | RADEON_LVDS_EN);
> +
> +                   /* zzz jrd cf kernel code */
> +                   tmp &= ~(RADEON_LVDS_BL_MOD_EN);
>                    OUTREG(RADEON_LVDS_GEN_CNTL, tmp);
> +
> +                   usleep(100);
> +
> +                   tmp &= ~(RADEON_LVDS_ON | RADEON_LVDS_EN);
> +
> +                   OUTREG(RADEON_LVDS_GEN_CNTL, tmp);
> +
>                    save->lvds_gen_cntl |= RADEON_LVDS_DISPLAY_DIS;
>                    save->lvds_gen_cntl &= ~(RADEON_LVDS_ON | RADEON_LVDS_BLON | RADEON_LVDS_EN);
>                    if (info->IsMobility || info->IsIGP) {
>
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