On 2/26/2024 23:28, Jani Nikula wrote:
Add a function to return the expected child device size. Flip the if
ladder around and use the same versions as in documentation to make it
easier to verify. Return an error for unknown versions. No functional
changes.
v2: Move BUILD_BUG_ON() next to the expected sizes
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_bios.c | 40 ++++++++++++++---------
1 file changed, 24 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index c0f41bd1f946..343726de9aa7 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -2699,27 +2699,35 @@ static void parse_ddi_ports(struct drm_i915_private *i915)
print_ddi_port(devdata);
}
+static int child_device_expected_size(u16 version)
+{
+ BUILD_BUG_ON(sizeof(struct child_device_config) < 40);
+
+ if (version > 256)
+ return -ENOENT;
+ else if (version >= 256)
Correct me if I'm wrong, but isn't version >= 256, a bit cryptic after
the first check?
Would it be wise to make it version > 256, return -ENOENT and if version
== 256, return 40?
+ return 40;
+ else if (version >= 216)
+ return 39;
+ else if (version >= 196)
+ return 38;
+ else if (version >= 195)
+ return 37;
+ else if (version >= 111)
+ return LEGACY_CHILD_DEVICE_CONFIG_SIZE;
+ else if (version >= 106)
+ return 27;
+ else
+ return 22;
+}
+
static bool child_device_size_valid(struct drm_i915_private *i915, int size)
{
int expected_size;
- if (i915->display.vbt.version < 106) {
- expected_size = 22;
- } else if (i915->display.vbt.version < 111) {
- expected_size = 27;
- } else if (i915->display.vbt.version < 195) {
- expected_size = LEGACY_CHILD_DEVICE_CONFIG_SIZE;
- } else if (i915->display.vbt.version == 195) {
- expected_size = 37;
- } else if (i915->display.vbt.version <= 215) {
- expected_size = 38;
- } else if (i915->display.vbt.version <= 255) {
- expected_size = 39;
- } else if (i915->display.vbt.version <= 256) {
- expected_size = 40;
- } else {
+ expected_size = child_device_expected_size(i915->display.vbt.version);
+ if (expected_size < 0) {
expected_size = sizeof(struct child_device_config);
- BUILD_BUG_ON(sizeof(struct child_device_config) < 40);
drm_dbg(&i915->drm,
"Expected child device config size for VBT version %u not known; assuming %d\n",
i915->display.vbt.version, expected_size);
--
-shekhar
