Re: [PATCHv3 28/30] drm/omap: fix display SYNC/DE flags

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Tomi,

Thank you for the patch.

On Tuesday 28 Mar 2017 16:08:14 Tomi Valkeinen wrote:
> At the moment VSYNC/HSYNC/DE high/low flags set by the panel/encoder
> drivers get lost when the videotimings are translated to DRM's
> videomode, as DRM's mode does not have corresponding flags.
> 
> DRM has bus-flags for this purpose, and while it lacks a few flags at
> the moment, it should be used here. However, until we rewrite omapdrm's
> device model, using bus-flags is rather difficult.
> 
> As a short term fix, this patch makes sure that every time the videomode
> is set in omap_crtc_mode_set_nofb(), the driver asks for the SYNC/DE
> flags from the panel/encoder drivers, and thus we get the correct flags
> into use.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> ---
>  drivers/gpu/drm/omapdrm/omap_connector.c |  2 --
>  drivers/gpu/drm/omapdrm/omap_crtc.c      | 28 +++++++++++++++++++++++++---
>  2 files changed, 25 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/omap_connector.c
> b/drivers/gpu/drm/omapdrm/omap_connector.c index 50d2b641c28b..d62c035f050f
> 100644
> --- a/drivers/gpu/drm/omapdrm/omap_connector.c
> +++ b/drivers/gpu/drm/omapdrm/omap_connector.c
> @@ -146,8 +146,6 @@ static int omap_connector_mode_valid(struct
> drm_connector *connector, int r, ret = MODE_BAD;
> 
>  	drm_display_mode_to_videomode(mode, &vm);
> -	vm.flags |= DISPLAY_FLAGS_DE_HIGH | DISPLAY_FLAGS_PIXDATA_POSEDGE |
> -		    DISPLAY_FLAGS_SYNC_NEGEDGE;

The dssdrv->get_timings() call below will return a video mode with polarity 
flags set, which will then be compared to vm. As you don't set the vm flags 
anymore, won't the comparison fail ?

>  	mode->vrefresh = drm_mode_vrefresh(mode);
> 
>  	/*
> diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c
> b/drivers/gpu/drm/omapdrm/omap_crtc.c index 1db96b077ae8..606ef807741a
> 100644
> --- a/drivers/gpu/drm/omapdrm/omap_crtc.c
> +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
> @@ -373,6 +373,11 @@ static void omap_crtc_mode_set_nofb(struct drm_crtc
> *crtc) {
>  	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
>  	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
> +	struct omap_drm_private *priv = crtc->dev->dev_private;
> +	const u32 flags_mask = DISPLAY_FLAGS_DE_HIGH | DISPLAY_FLAGS_DE_LOW |
> +		DISPLAY_FLAGS_PIXDATA_POSEDGE | DISPLAY_FLAGS_PIXDATA_NEGEDGE 
|
> +		DISPLAY_FLAGS_SYNC_POSEDGE | DISPLAY_FLAGS_SYNC_NEGEDGE;
> +	int i;

i only takes positive values, you can make it an unsigned int.

> 
>  	DBG("%s: set mode: %d:\"%s\" %d %d %d %d %d %d %d %d %d %d 0x%x 0x%x",
>  	    omap_crtc->name, mode->base.id, mode->name,
> @@ -382,9 +387,26 @@ static void omap_crtc_mode_set_nofb(struct drm_crtc
> *crtc) mode->type, mode->flags);
> 
>  	drm_display_mode_to_videomode(mode, &omap_crtc->vm);
> -	omap_crtc->vm.flags |= DISPLAY_FLAGS_DE_HIGH |
> -			       DISPLAY_FLAGS_PIXDATA_POSEDGE |
> -			       DISPLAY_FLAGS_SYNC_NEGEDGE;
> +

Could you add a HACK/FIXME comment to explain how this should be fixed 
properly ? I want to make sure we won't forget to remove this hack.

> +	for (i = 0; i < priv->num_encoders; ++i) {
> +		struct drm_encoder *encoder = priv->encoders[i];
> +
> +		if (encoder->crtc == crtc) {
> +			struct omap_dss_device *dssdev;
> +
> +			dssdev = omap_encoder_get_dssdev(encoder);
> +
> +			if (dssdev) {
> +				struct videomode vm = {0};
> +
> +				dssdev->driver->get_timings(dssdev, &vm);
> +
> +				omap_crtc->vm.flags |= vm.flags & flags_mask;
> +			}
> +
> +			break;
> +		}
> +	}
>  }
> 
>  static int omap_crtc_atomic_check(struct drm_crtc *crtc,

-- 
Regards,

Laurent Pinchart

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