Patch "drm/i915/vbt: split out defaults that are set when there is no VBT" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

drm/i915/vbt: split out defaults that are set when there is no VBT

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-i915-vbt-split-out-defaults-that-are-set-when-there-is-no-vbt.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jani Nikula <[email protected]>
Date: Fri, 10 Mar 2017 15:27:58 +0200
Subject: drm/i915/vbt: split out defaults that are set when there is no VBT
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Jani Nikula <[email protected]>

commit bb1d132935c2f87cd261eb559759fe49d5e5dc43 upstream.

The main thing are the DDI ports. If there's a VBT that says there are no outputs, we should trust that, and not have semi-random defaults. Unfortunately, the defaults have resulted in some Chromebooks without VBT to rely on this behaviour, so we split out the defaults for the missing VBT case.

---
 drivers/gpu/drm/i915/intel_bios.c |   17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

@@ -1332,6 +1332,7 @@ parse_device_mapping(struct drm_i915_pri
 	return;
 }
 
+/* Common defaults which may be overridden by VBT. */
 static void
 init_vbt_defaults(struct drm_i915_private *dev_priv)
 {

@@ -1368,6 +1369,18 @@ init_vbt_defaults(struct drm_i915_privat
 			&dev_priv->vbt.ddi_port_info[port];
 
 		info->hdmi_level_shift = HDMI_LEVEL_SHIFT_UNKNOWN;
+	}
+}
+
+/* Defaults to initialize only if there is no VBT. */
+static void
+init_vbt_missing_defaults(struct drm_i915_private *dev_priv)
+{
+	enum port port;
+
+	for (port = PORT_A; port < I915_MAX_PORTS; port++) {
+		struct ddi_vbt_port_info *info =
+			&dev_priv->vbt.ddi_port_info[port];
 
 		info->supports_dvi = (port != PORT_A && port != PORT_E);
 		info->supports_hdmi = info->supports_dvi;

@@ -1504,8 +1517,10 @@ void intel_bios_init(struct drm_i915_pri
 	parse_ddi_ports(dev_priv, bdb);
 
 out:
-	if (!vbt)
+	if (!vbt) {
 		DRM_INFO("Failed to find VBIOS tables (VBT)\n");
+		init_vbt_missing_defaults(dev_priv);
+	}
 
 	if (bios)
 		pci_unmap_rom(pdev, bios);

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/drm-i915-vbt-don-t-propagate-errors-from-intel_bios_init.patch queue-4.9/drm-i915-vbt-split-out-defaults-that-are-set-when-there-is-no-vbt.patch