Re: [PATCH v2 2/2] drm/i915/vlv: Reset the ADPA in vlv_display_power_well_init()

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@vger.kernel.org Signed-off-by: Lyude cpaul@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