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

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Sep 12, 2012 at 08:04:42AM -0700, Jesse Barnes wrote:
> 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>

Applied to -fixes, but not yet pushed (since Dave hasn't pulled the old
-fixes tree yet).
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch