[Intel-gfx] [PATCH] drm/i915/fbdev: Actually configure untiled displays

[Chris Wilson]

Quoting Maarten Lankhorst (2019-02-15 16:02:40)
> Op 15-02-2019 om 13:30 schreef Chris Wilson:
> > If we skipped all the connectors that were not part of a tile, we would
> > leave conn_seq=0 and conn_configured=0, convincing ourselves that we
> > had stagnated in our configuration attempts. Avoid this situation by
> > starting conn_seq=ALL_CONNECTORS, and repeating until we find no more
> > connectors to configure.
> >
> > Fixes: 754a76591b12 ("drm/i915/fbdev: Stop repeating tile configuration on stagnation")
> > Reported-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_fbdev.c | 12 +++++++-----
> >  1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
> > index 376ffe842e26..e8f694b57b8a 100644
> > --- a/drivers/gpu/drm/i915/intel_fbdev.c
> > +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> > @@ -338,8 +338,8 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> >                                   bool *enabled, int width, int height)
> >  {
> >       struct drm_i915_private *dev_priv = to_i915(fb_helper->dev);
> > -     unsigned long conn_configured, conn_seq, mask;
> >       unsigned int count = min(fb_helper->connector_count, BITS_PER_LONG);
> > +     unsigned long conn_configured, conn_seq;
> >       int i, j;
> >       bool *save_enabled;
> >       bool fallback = true, ret = true;
> > @@ -357,10 +357,9 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> >               drm_modeset_backoff(&ctx);
> >  
> >       memcpy(save_enabled, enabled, count);
> > -     mask = GENMASK(count - 1, 0);
> > +     conn_seq = GENMASK(count - 1, 0);
> >       conn_configured = 0;
> >  retry:
> > -     conn_seq = conn_configured;
> >       for (i = 0; i < count; i++) {
> >               struct drm_fb_helper_connector *fb_conn;
> >               struct drm_connector *connector;
> > @@ -373,7 +372,8 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> >               if (conn_configured & BIT(i))
> >                       continue;
> >  
> > -             if (conn_seq == 0 && !connector->has_tile)
> > +             /* First pass, only consider tiled connectors */
> > +             if (conn_seq == GENMASK(count - 1, 0) && !connector->has_tile)
> >                       continue;
> >  
> >               if (connector->status == connector_status_connected)
> > @@ -477,8 +477,10 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> >               conn_configured |= BIT(i);
> >       }
> >  
> > -     if ((conn_configured & mask) != mask && conn_configured != conn_seq)
> > +     if (conn_configured != conn_seq) { /* repeat until no more are found */
> > +             conn_seq = conn_configured;
> >               goto retry;
> > +     }
> >  
> >       /*
> >        * If the BIOS didn't enable everything it could, fall back to have the
> 
> Also Cc: <stable at vger.kernel.org> # v3.19+ , because it fixes a previous stable fix?

I put the fixes there, the rest I leave to maintainers and AUTOSEL :-p
-Chris