Re: [BISECTED, -next] drm/i915: blurred HDMI output

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Sun, 17 Oct 2010 19:37:13 +0200
Arnd Bergmann <arnd@arndb.de> wrote:

> Commit e9e331a8ab "drm/i915/lvds: Ensure panel is unlocked for Ironlake or
> the panel fitter" broke my HDMI output on GMA4500HD, it seemed to be driving
> the output with the wrong resolution, while still showing the native panel
> resolution of 1680x1050 being in use. This caused a very irritating blur
> on the screen.
> 
> After bisecting the problem, I managed to do a partial revert which fixes
> the problem and applies on top of linux-next. I have no idea what this patch
> actually does or if it can break any other configuration, but it solves the
> problem for me.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 9109c00..2d47161 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3921,6 +3921,10 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
>  	pipeconf |= PIPECONF_ENABLE;
>  	dpll |= DPLL_VCO_ENABLE;
>  
> +	/* Disable the panel fitter if it was on our pipe */
> +	if (!HAS_PCH_SPLIT(dev) && intel_panel_fitter_pipe(dev) == pipe)
> +		I915_WRITE(PFIT_CONTROL, 0);
> +
>  	DRM_DEBUG_KMS("Mode for pipe %c:\n", pipe == 0 ? 'A' : 'B');
>  	drm_mode_debug_printmodeline(mode);
>  
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 40e99bf..de21a82 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -224,6 +224,7 @@ extern u32 intel_panel_get_max_backlight(struct drm_device *dev);
>  extern u32 intel_panel_get_backlight(struct drm_device *dev);
>  extern void intel_panel_set_backlight(struct drm_device *dev, u32 level);
>  
> +extern int intel_panel_fitter_pipe (struct drm_device *dev);
>  extern void intel_crtc_load_lut(struct drm_crtc *crtc);
>  extern void intel_encoder_prepare (struct drm_encoder *encoder);
>  extern void intel_encoder_commit (struct drm_encoder *encoder);
> diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
> index 375316a..da65d95 100644
> --- a/drivers/gpu/drm/i915/intel_overlay.c
> +++ b/drivers/gpu/drm/i915/intel_overlay.c
> @@ -1053,7 +1053,7 @@ static int check_overlay_src(struct drm_device *dev,
>   * Return the pipe currently connected to the panel fitter,
>   * or -1 if the panel fitter is not present or not in use
>   */
> -static int intel_panel_fitter_pipe(struct drm_device *dev)
> +int intel_panel_fitter_pipe(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	u32  pfit_control;
> 

Hm, the LVDS code should take care of panel fitting in
the !HAS_PCH_SPLIT case.  Does this patch achieve the same thing as
yours?  Maybe we were leaving a stale PFIT value in place...

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds
index f1a6499..bc1e1c1 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -1000,6 +1000,8 @@ void intel_lvds_init(struct drm_device *dev)
        if (!intel_lvds->fixed_mode)
                goto failed;
 
+       intel_lvds->pfit_dirty = true;
+
 out:
        if (HAS_PCH_SPLIT(dev)) {
                u32 pwm;