[Intel-gfx] [PATCH 2/2] drm/i915: Disable active links before rebooting

[Ville Syrjälä]

On Mon, Nov 26, 2018 at 02:55:54PM +0200, Jani Nikula wrote:
> On Sun, 25 Nov 2018, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > Certain monitors, e.g. Dell, do not like it when we reboot with an
> > active link, leaving them in a confused state where they refuse to
> > renegotiate the link after the reboot. If we hook into the reboot
> > notifier, we can switch off any active link before rebooting, leaving
> > everything in a consistent, hopefully happy, state.
> 
> Hmm, we already have this overly specific reboot notifier in intel_dp.c
> for vlv/chv. I guess we should generalize these somehow.

The earlier discussion we had on this topic:
https://lists.freedesktop.org/archives/intel-gfx/2016-August/102461.html
https://lists.freedesktop.org/archives/intel-gfx/2016-August/103145.html

Anyone have time to resurrect/rework that? I guess simply ignoring
the hpd issues for now is better than ignoring the entire problem.

> 
> BR,
> Jani.
> 
> 
> >
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_pci.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> > index cf2396856d38..e4248adb2032 100644
> > --- a/drivers/gpu/drm/i915/i915_pci.c
> > +++ b/drivers/gpu/drm/i915/i915_pci.c
> > @@ -26,6 +26,8 @@
> >  #include <linux/vgaarb.h>
> >  #include <linux/vga_switcheroo.h>
> >  
> > +#include <drm/drm_atomic_helper.h>
> > +
> >  #include "i915_drv.h"
> >  #include "i915_selftest.h"
> >  
> > @@ -774,6 +776,9 @@ static void i915_pci_shutdown(struct pci_dev *pdev)
> >  	/* Cancel any outstanding rendering */
> >  	if (READ_ONCE(i915->gt.awake))
> >  		i915_gem_set_wedged(i915);
> > +
> > +	/* Disable active links to avoid confusing certain (Dell) monitors */
> > +	drm_atomic_helper_shutdown(&i915->drm);
> >  }
> >  
> >  static struct pci_driver i915_pci_driver = {
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel