[PATCH 07/36] drm/omap: Init fbdev emulation only when we have displays

[Daniel Vetter]

On Fri, Dec 09, 2016 at 01:13:11PM +0200, Tomi Valkeinen wrote:
> On 30/11/16 15:46, Daniel Vetter wrote:
> > On Wed, Nov 30, 2016 at 01:17:09PM +0200, Tomi Valkeinen wrote:
> >> From: Peter Ujfalusi <peter.ujfalusi at ti.com>
> >>
> >> Do not try to init the fbdev if either num_crtcs or num_connectors is 0.
> >> In this case we do not have display so the fbdev init would fail anyways.
> >>
> >> Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
> >> ---
> >>  drivers/gpu/drm/omapdrm/omap_fbdev.c | 3 +++
> >>  1 file changed, 3 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> >> index 8d8ac173f55d..2b045262f8ad 100644
> >> --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> >> +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> >> @@ -255,6 +255,9 @@ struct drm_fb_helper *omap_fbdev_init(struct drm_device *dev)
> >>  	struct drm_fb_helper *helper;
> >>  	int ret = 0;
> >>  
> >> +	if (!priv->num_crtcs || !priv->num_connectors)
> >> +		return NULL;
> > 
> > Thierry Redding had patches to implement this in a generic fashion in the
> > fbdev emulation (just wait with fbdev init until the first screen shows
> > up). Would be great to polish up that work (I've reviewed the original
> > series already) and land it, instead of driver hacks forever.
> > 
> > https://patchwork.freedesktop.org/patch/91448/
> 
> This is not doing the same thing, or at least the point is not the same.
> 
> OMAP DSS has writeback support, which can be used in a plain
> memory-to-memory mode (not yet in the mainline, though). The need for
> this patch came up when people tried to use WB on boards that don't have
> any displays.
> 
> So this was not about deferred setup but skipping fbdev totally if we
> don't have any display outputs.

ah ok. Would still fix both problems ;-) But I understand that a more
direct solution here makes more sense.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch