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authorDavid Weinehall <david.weinehall@linux.intel.com>2015-08-04 16:55:52 +0300
committerDaniel Vetter <daniel.vetter@ffwll.ch>2015-08-06 17:28:26 +0200
commit047fe6e6db9161e69271f56daaafdaf2add023b1 (patch)
treeb01e4d74d09bf946b824465be75c2be473cee6c3
parent5eb3e5a5e11d14f9deb2a4b83555443b69ab9940 (diff)
downloadlinux-stericsson-047fe6e6db9161e69271f56daaafdaf2add023b1.tar.gz
drm/i915: Allow parsing of variable size child device entries from VBT
VBT version 196 increased the size of common_child_dev_config. The parser code assumed that the size of this structure would not change. The modified code now copies the amount needed based on the VBT version, and emits a debug message if the VBT version is unknown (too new); since the struct config block won't shrink in newer versions it should be harmless to copy the maximum known size in such cases, so that's what we do, but emitting the warning is probably sensible anyway. In the longer run it might make sense to modify the parser code to use a version/feature mapping, rather than hardcoding things like this, but for now the variants are fairly managable. This fixes a regression introduced in commit 90e4f1592bb6e82f6690f0e05a8aadcf04d7bce7 Author: Ville Syrjälä <ville.syrjala@linux.intel.com> Date: Wed Mar 25 18:45:58 2015 +0200 drm/i915: Fix the VBT child device parsing for BSW since we're hitting a DRM_ERROR on older platforms with this. v2: Stricter size checks Signed-off-by: David Weinehall <david.weinehall@linux.intel.com> [danvet: Fixup format string.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-rw-r--r--drivers/gpu/drm/i915/intel_bios.c27
1 files changed, 23 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 198fc3c3291b..3dcd59e694db 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1075,15 +1075,34 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
const union child_device_config *p_child;
union child_device_config *child_dev_ptr;
int i, child_device_num, count;
- u16 block_size;
+ u8 expected_size;
+ u16 block_size;
p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
if (!p_defs) {
DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
return;
}
- if (p_defs->child_dev_size < sizeof(*p_child)) {
- DRM_ERROR("General definiton block child device size is too small.\n");
+ if (bdb->version < 195) {
+ expected_size = 33;
+ } else if (bdb->version == 195) {
+ expected_size = 37;
+ } else if (bdb->version <= 197) {
+ expected_size = 38;
+ } else {
+ expected_size = 38;
+ DRM_DEBUG_DRIVER("Expected child_device_config size for BDB version %u not known; assuming %u\n",
+ expected_size, bdb->version);
+ }
+
+ if (expected_size > sizeof(*p_child)) {
+ DRM_ERROR("child_device_config cannot fit in p_child\n");
+ return;
+ }
+
+ if (p_defs->child_dev_size != expected_size) {
+ DRM_ERROR("Size mismatch; child_device_config size=%u (expected %u); bdb->version: %u\n",
+ p_defs->child_dev_size, expected_size, bdb->version);
return;
}
/* get the block size of general definitions */
@@ -1130,7 +1149,7 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
child_dev_ptr = dev_priv->vbt.child_dev + count;
count++;
- memcpy(child_dev_ptr, p_child, sizeof(*p_child));
+ memcpy(child_dev_ptr, p_child, p_defs->child_dev_size);
}
return;
}