Patch "drm/i915: Fix not finding the VBT when it overlaps with OPREGION_ASLE_EXT" has been added to the 4.10-stable tree

[<gregkh@linuxfoundation.org>]

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

    drm/i915: Fix not finding the VBT when it overlaps with OPREGION_ASLE_EXT

to the 4.10-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-fix-not-finding-the-vbt-when-it-overlaps-with-opregion_asle_ext.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 998d75730b40afc218c059d811869abe9676b305 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Tue, 14 Feb 2017 18:12:38 +0200
Subject: drm/i915: Fix not finding the VBT when it overlaps with OPREGION_ASLE_EXT

From: Hans de Goede <hdegoede@redhat.com>

commit 998d75730b40afc218c059d811869abe9676b305 upstream.

If there is no OPREGION_ASLE_EXT then a VBT stored in mailbox #4 may
use the ASLE_EXT parts of the opregion. Adjust the vbt_size calculation
for a vbt in mailbox #4 for this.

This fixes the driver not finding the VBT on a jumper ezpad mini3
cherrytrail tablet and on a ACER SW5_017 machine.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1487088758-30050-1-git-send-email-jani.nikula@intel.com
(cherry picked from commit dfb65e71ea2c1d97ac373cc0587dc60b3307581a)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/i915/intel_opregion.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/intel_opregion.c
+++ b/drivers/gpu/drm/i915/intel_opregion.c
@@ -982,7 +982,18 @@ int intel_opregion_setup(struct drm_i915
 			opregion->vbt_size = vbt_size;
 		} else {
 			vbt = base + OPREGION_VBT_OFFSET;
-			vbt_size = OPREGION_ASLE_EXT_OFFSET - OPREGION_VBT_OFFSET;
+			/*
+			 * The VBT specification says that if the ASLE ext
+			 * mailbox is not used its area is reserved, but
+			 * on some CHT boards the VBT extends into the
+			 * ASLE ext area. Allow this even though it is
+			 * against the spec, so we do not end up rejecting
+			 * the VBT on those boards (and end up not finding the
+			 * LCD panel because of this).
+			 */
+			vbt_size = (mboxes & MBOX_ASLE_EXT) ?
+				OPREGION_ASLE_EXT_OFFSET : OPREGION_SIZE;
+			vbt_size -= OPREGION_VBT_OFFSET;
 			if (intel_bios_is_valid_vbt(vbt, vbt_size)) {
 				DRM_DEBUG_KMS("Found valid VBT in ACPI OpRegion (Mailbox #4)\n");
 				opregion->vbt = vbt;


Patches currently in stable-queue which might be from hdegoede@redhat.com are

queue-4.10/drm-i915-fix-not-finding-the-vbt-when-it-overlaps-with-opregion_asle_ext.patch