On Fri, Apr 15, 2016 at 03:40:10PM -0400, Lyude wrote:
> While VGA hotplugging worked(ish) before, it looks like that was mainly
> because we'd unintentionally enable it in
> valleyview_crt_detect_hotplug() when we did a force trigger. This
> doesn't work reliably enough because whenever the display powerwell on
> vlv gets disabled, the values set in VLV_ADPA get cleared and
> consequently VGA hotplugging gets disabled. This causes bugs such as one
> we found on an Intel NUC, where doing the following sequence of
> hotplugs:
>
> - Disconnect all monitors
> - Connect VGA
> - Disconnect VGA
> - Connect HDMI
>
> Would result in VGA hotplugging becoming disabled, due to the powerwells
> getting toggled in the process of connecting HDMI.
>
> Changes since v1:
> - Instead of handling the register writes ourself, we just reuse
> intel_crt_detect()
> - Instead of resetting the ADPA during display IRQ installation, we now
> reset them in vlv_display_power_well_init()
>
> CC: stable at vger.kernel.org
> Signed-off-by: Lyude <cpaul at redhat.com>
> ---
> drivers/gpu/drm/i915/intel_runtime_pm.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c
> b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 80e8bd4..c7d195f 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -902,6 +902,7 @@ static bool vlv_power_well_enabled(struct
> drm_i915_private *dev_priv,
>
> static void vlv_display_power_well_init(struct drm_i915_private *dev_priv)
> {
> + struct drm_encoder *encoder, *vga_encoder = NULL;
> enum pipe pipe;
>
> /*
> @@ -935,6 +936,17 @@ static void vlv_display_power_well_init(struct
> drm_i915_private *dev_priv)
>
> intel_hpd_init(dev_priv);
>
> + /* Re-enable the ADPA, if we have one */
> + drm_for_each_encoder(encoder, dev_priv->dev) {
> + if (encoder->encoder_type == DRM_MODE_ENCODER_DAC) {
> + vga_encoder = encoder;
> + break;
> + }
> + }
> +
> + if (vga_encoder && vga_encoder->funcs->reset)
> + vga_encoder->funcs->reset(vga_encoder);
> +
Something like
struct intel_encoder *encoder;
...
for_each_intel_encoder(encoder) {
if (encoder->type == ANALOG)
intel_crt_reset(&encoder->base);
}
would be neater in my eyes.
> i915_redisable_vga_power_on(dev_priv->dev);
> }
>
> --
> 2.5.5
--
Ville Syrjälä
Intel OTC
