[PATCH] radeon: Release DDC i2c lines after probe

[Mike A. Harris]

Benjamin Herrenschmidt wrote:
> (Hui: any comment on this one ?)
> 
> This patch fixes support of recent Apple Cinema Display monitors.
> Previously, we used to keep the SDA and SDL lines of the i2c "asserted"
> after probing. This causes those monitor to shut down after a second or
> so. This patch makes us "release" the line back to hi-z state (and thus
> pulled high) after we are done probing a connector and fixes the problem
> with Apple displays. (This should probably be applied to the stable
> branch as well).
> 
> Index: xc/programs/Xserver/hw/xfree86/drivers/ati/radeon_driver.c
> ===================================================================
> --- xc.orig/programs/Xserver/hw/xfree86/drivers/ati/radeon_driver.c	2005-04-04 10:18:39.000000000 +1000
> +++ xc/programs/Xserver/hw/xfree86/drivers/ati/radeon_driver.c	2005-04-04 10:35:07.000000000 +1000
> @@ -1006,6 +1006,9 @@
>  	MonType = MT_NONE;
>      }
>  
> +    OUTREG(info->DDCReg, INREG(info->DDCReg) &
> +	   ~(RADEON_GPIO_EN_0 | RADEON_GPIO_EN_1));
> +
>      if (*MonInfo) {
>  	if ((*MonInfo)->rawData[0x14] & 0x80) {
>  	    /* Note some laptops have a DVI output that uses internal TMDS,

We've had several people report this bug.  ;o)  Please make sure
this gets filed in bugzilla if it isn't in CVS already.  ;o)