Re: [PATCH] drm/i915: enable lvds pin pairs before dpll on gen2

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Tue, 11 Sep 2012 12:37:55 +0200
Daniel Vetter <daniel.vetter@ffwll.ch> wrote:

> Otherwise things migt not work too well.
> 
> Breakage introduced in
> 
> commit eb1cbe4848b01f9f073064377875bc7d71eb401b
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> Date:   Wed Mar 28 23:12:16 2012 +0200
> 
>     drm/i915: split PLL update code out of i9xx_crtc_mode_set
> 
> Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> Cc: stable@vger.kernel.org (for 3.5 only)
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 6be59cf..4c4a88b 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -4227,12 +4227,6 @@ static void i8xx_update_pll(struct drm_crtc *crtc,
>  	POSTING_READ(DPLL(pipe));
>  	udelay(150);
>  
> -	I915_WRITE(DPLL(pipe), dpll);
> -
> -	/* Wait for the clocks to stabilize. */
> -	POSTING_READ(DPLL(pipe));
> -	udelay(150);
> -
>  	/* The LVDS pin pair needs to be on before the DPLLs are enabled.
>  	 * This is an exception to the general rule that mode_set doesn't turn
>  	 * things on.
> @@ -4240,6 +4234,12 @@ static void i8xx_update_pll(struct drm_crtc *crtc,
>  	if (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS))
>  		intel_update_lvds(crtc, clock, adjusted_mode);
>  
> +	I915_WRITE(DPLL(pipe), dpll);
> +
> +	/* Wait for the clocks to stabilize. */
> +	POSTING_READ(DPLL(pipe));
> +	udelay(150);
> +
>  	/* The pixel multiplier can only be updated once the
>  	 * DPLL is enabled and the clocks are stable.
>  	 *

Looks fine.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center