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

[Dave Airlie]

This patch broke userspace. I'm reverting it.

I know userspace was broken, but since it's a userspace lots of people
are using we shouldn't break it.

We either need to add this as a config option that we can let people
pick the breakage, or detect broken userspace somehow and magic around
it.

But breaking it isn't happening here. I reported this weeks ago, and I
got regression dodging behaviour.

Dave.

On Sun, 17 Feb 2019 at 03:09, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>
> Quoting Chris Wilson (2019-02-15 16:06:59)
> > 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
>
> Pushed with cc:stable. Thanks for spotting it,
> -Chris
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