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authorHans de Goede <hdegoede@redhat.com>2017-02-14 19:12:38 +0300
committerJani Nikula <jani.nikula@intel.com>2017-02-15 12:29:04 +0300
commitdfb65e71ea2c1d97ac373cc0587dc60b3307581a (patch)
tree5d2ea3900cd1957f08de030e39c6fb0a0b715424 /drivers/gpu/drm/i915/intel_opregion.c
parent4ac9659ef9f110a8f651e5a75c24e1ac439b44ff (diff)
downloadlinux-dfb65e71ea2c1d97ac373cc0587dc60b3307581a.tar.xz
drm/i915: Fix not finding the VBT when it overlaps with OPREGION_ASLE_EXT
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. Cc: stable@vger.kernel.org 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
Diffstat (limited to 'drivers/gpu/drm/i915/intel_opregion.c')
-rw-r--r--drivers/gpu/drm/i915/intel_opregion.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
index f4429f67a4e3..4a862a358c70 100644
--- 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_private *dev_priv)
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;