On Thu, May 28, 2026 at 12:48:37PM +0200, Walter Alejandro Iglesias wrote:
> On Wed, May 27, 2026 at 08:51:29PM +0300, Vitaliy Makkoveev wrote:
> > On Wed, May 27, 2026 at 07:27:47PM +0200, Walter Alejandro Iglesias wrote:
> > > 
> > > I found a function defined in ../drm/drm_fb_helper.c,
> > > drm_fb_helper_restore_fbdev_mode_unlocked() which restores the entire
> > > fbdev display mode (including size).
> > > 
> > 
> > Thanks, this diff completely fixes my issue. ok mvs@
> > 
> > > Index: i915_driver.c
> > > ===================================================================
> > > RCS file: /cvs/src/sys/dev/pci/drm/i915/i915_driver.c,v
> > > diff -u -p -u -p -r1.30 i915_driver.c
> > > --- i915_driver.c	30 Apr 2026 04:33:06 -0000	1.30
> > > +++ i915_driver.c	27 May 2026 13:32:34 -0000
> > > @@ -2154,8 +2154,14 @@ inteldrm_burner_cb(void *arg1)
> > >  	struct drm_i915_private *dev_priv = arg1;
> > >  	struct drm_device *dev = &dev_priv->drm;
> > >  	struct drm_fb_helper *helper = dev->fb_helper;
> > > +	struct rasops_info *ri = &dev_priv->ro;
> > >  
> > >  	drm_fb_helper_blank(dev_priv->burner_fblank, helper->info);
> > > +
> > > +	if (dev_priv->burner_fblank == FB_BLANK_UNBLANK) {
> > > +		drm_fb_helper_restore_fbdev_mode_unlocked(helper);
> > > +		rasops_show_screen(ri, ri->ri_active, 0, NULL, NULL);
> > > +	}
> > >  }
> > >  
> > >  int
> 
> 
> To confirm your Alder Lake suffers from two different issues.  I'd like
> to know what happens if we remove rasops_show_screen from the diff.
> This should avoid the Alder Lake half-line on top but not the ghosting.
> 

No ghosting, no half-line. On both machines. 

> 
> Index: i915_driver.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/drm/i915/i915_driver.c,v
> diff -u -p -u -p -r1.30 i915_driver.c
> --- i915_driver.c	30 Apr 2026 04:33:06 -0000	1.30
> +++ i915_driver.c	28 May 2026 10:41:46 -0000
> @@ -2156,6 +2156,8 @@ inteldrm_burner_cb(void *arg1)
>  	struct drm_fb_helper *helper = dev->fb_helper;
>  
>  	drm_fb_helper_blank(dev_priv->burner_fblank, helper->info);
> +	if (dev_priv->burner_fblank == FB_BLANK_UNBLANK && helper)
                                                           ^^^^^^
 This check is useless, we have `helper' dereference in previous line.
> +		drm_fb_helper_restore_fbdev_mode_unlocked(helper);
>  }
>  
>  int
> 
> 
> 
> 
> -- 
> Walter