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

[Jani Nikula]

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.

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