path: root/drivers/gpu/drm/i915/intel_bios.h
diff options
authorPaulo Zanoni <paulo.r.zanoni@intel.com>2013-09-11 18:02:47 -0300
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-10-01 07:45:04 +0200
commit768f69c9fe601af39dfeb377f45909896f201444 (patch)
treece10f4bd9733cd6620360918d215decc404cc9b3 /drivers/gpu/drm/i915/intel_bios.h
parentf740334775efd30631c556f7654b92dae66df494 (diff)
drm/i915: VBT's child_device_config changes over time
We currently treat the child_device_config as a simple struct, but this is not correct: new BDB versions change the meaning of some offsets, so the struct needs to be adjusted for each version. Since there are too many changes (today we're in version 170!), making a big versioned union would be too complicated, so child_device_config is now a union of 3 things: (i) a "raw" byte array that's safe to use anywhere; (ii) an "old" structure that's the one we've been using and should be safe to keep in the SDVO and TV code; and (iii) a "common" structure that should contain only fields that are common for all the known VBT versions. Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_bios.h')
1 files changed, 31 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index 6e9250eb9c2..1da2bf20829 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -202,7 +202,10 @@ struct bdb_general_features {
#define DEVICE_PORT_DVOB 0x01
#define DEVICE_PORT_DVOC 0x02
-struct child_device_config {
+/* We used to keep this struct but without any version control. We should avoid
+ * using it in the future, but it should be safe to keep using it in the old
+ * code. */
+struct old_child_dev_config {
u16 handle;
u16 device_type;
u8 device_id[10]; /* ascii string */
@@ -224,6 +227,32 @@ struct child_device_config {
u8 dvo_function;
} __attribute__((packed));
+/* This one contains field offsets that are known to be common for all BDB
+ * versions. Notice that the meaning of the contents contents may still change,
+ * but at least the offsets are consistent. */
+struct common_child_dev_config {
+ u16 handle;
+ u16 device_type;
+ u8 not_common1[12];
+ u8 dvo_port;
+ u8 not_common2[2];
+ u8 ddc_pin;
+ u16 edid_ptr;
+} __attribute__((packed));
+/* This field changes depending on the BDB version, so the most reliable way to
+ * read it is by checking the BDB version and reading the raw pointer. */
+union child_device_config {
+ /* This one is safe to be used anywhere, but the code should still check
+ * the BDB version. */
+ u8 raw[33];
+ /* This one should only be kept for legacy code. */
+ struct old_child_dev_config old;
+ /* This one should also be safe to use anywhere, even without version
+ * checks. */
+ struct common_child_dev_config common;
struct bdb_general_definitions {
/* DDC GPIO */
u8 crt_ddc_gmbus_pin;
@@ -249,7 +278,7 @@ struct bdb_general_definitions {
* number = (block_size - sizeof(bdb_general_definitions))/
* sizeof(child_device_config);
- struct child_device_config devices[0];
+ union child_device_config devices[0];
} __attribute__((packed));
struct bdb_lvds_options {