Re: [PATCH] drm/i915: Don't check gmch state on inherited configs

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Sun, Apr 13, 2014 at 12:00:33PM +0200, Daniel Vetter wrote:
> ... our current modeset code isn't good enough yet to handle this. The
> scenario is:
> 
> 1. BIOS sets up a cloned config with lvds+external screen on the same
> pipe, e.g. pipe B.
> 
> 2. We read out that state for pipe B and assign the gmch_pfit state to
> it.
> 
> 3. The initial modeset switches the lvds to pipe A but due to lack of
> atomic modeset we don't recompute the config of pipe B.
> 
> -> both pipes now claim (in the sw pipe config structure) to use the
> gmch_pfit, which just won't work.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74081
> Cc: Alan Stern <stern@rowland.harvard.edu>
> Cc: stable@vger.kernel.org
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Right. Until we get atomic modeset this seems like the least hackish
thing to do.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/intel_display.c | 23 ++++++++++++++++++-----
>  drivers/gpu/drm/i915/intel_drv.h     |  3 ++-
>  2 files changed, 20 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 1390ab5e00dc..7b7987dc65ba 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -9655,11 +9655,22 @@ intel_pipe_config_compare(struct drm_device *dev,
>  	PIPE_CONF_CHECK_I(pipe_src_w);
>  	PIPE_CONF_CHECK_I(pipe_src_h);
>  
> -	PIPE_CONF_CHECK_I(gmch_pfit.control);
> -	/* pfit ratios are autocomputed by the hw on gen4+ */
> -	if (INTEL_INFO(dev)->gen < 4)
> -		PIPE_CONF_CHECK_I(gmch_pfit.pgm_ratios);
> -	PIPE_CONF_CHECK_I(gmch_pfit.lvds_border_bits);
> +	/*
> +	 * FIXME: BIOS likes to set up a cloned config with lvds+external
> +	 * screen. Since we don't yet re-compute the pipe config when moving
> +	 * just the lvds port away to another pipe the sw tracking won't match.
> +	 *
> +	 * Proper atomic modesets with recomputed global state will fix this.
> +	 * Until then just don't check gmch state for inherited modes.
> +	 */
> +	if (!PIPE_CONF_QUIRK(PIPE_CONFIG_QUIRK_INHERITED_MODE)) {
> +		PIPE_CONF_CHECK_I(gmch_pfit.control);
> +		/* pfit ratios are autocomputed by the hw on gen4+ */
> +		if (INTEL_INFO(dev)->gen < 4)
> +			PIPE_CONF_CHECK_I(gmch_pfit.pgm_ratios);
> +		PIPE_CONF_CHECK_I(gmch_pfit.lvds_border_bits);
> +	}
> +
>  	PIPE_CONF_CHECK_I(pch_pfit.enabled);
>  	if (current_config->pch_pfit.enabled) {
>  		PIPE_CONF_CHECK_I(pch_pfit.pos);
> @@ -11618,6 +11629,8 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
>  			    base.head) {
>  		memset(&crtc->config, 0, sizeof(crtc->config));
>  
> +		crtc->config.quirks |= PIPE_CONFIG_QUIRK_INHERITED_MODE;
> +
>  		crtc->active = dev_priv->display.get_pipe_config(crtc,
>  								 &crtc->config);
>  
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index c551472b892e..b885df150910 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -236,7 +236,8 @@ struct intel_crtc_config {
>  	 * tracked with quirk flags so that fastboot and state checker can act
>  	 * accordingly.
>  	 */
> -#define PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS (1<<0) /* unreliable sync mode.flags */
> +#define PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS	(1<<0) /* unreliable sync mode.flags */
> +#define PIPE_CONFIG_QUIRK_INHERITED_MODE	(1<<1) /* mode inherited from firmware */
>  	unsigned long quirks;
>  
>  	/* User requested mode, only valid as a starting point to
> -- 
> 1.8.4.rc3
> 
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-- 
Ville Syrjälä
Intel OTC